Browsing by Author "Harikrishnan, VS"

Now showing 1 - 19 of 19
  • Item
    Anaesthetic regimen for coronary stenting in porcine model
    (INDIAN VETERINARY JOURNAL, 2006) Harikrishnan, VS; Shenoy, SJ; Umashankar, PR
    Coronary stent is one of the medical devices that is used in the treatment of localized atherosclerotic plaques in coronary artery. A suitable animal model is an essential step involved in stabilizing the safety and efficacy of implants. Swine is the animal model of choice for cardiovascular implantables (Francis et al., 1986; Martin et al., 1995 and Hughes, 1986), and is used as the animal model for coronary stent evaluation (Schulz et al., 2000). Since the normal porcine coronary artery is hypersensitive to surgical manipulations and anaesthetics (Michael et al., 1986), swine is prone to cardiac fibrillations and dysrhythmias. Halothane sensitizes the myocardium to endogenous catacholamines such as adrenaline, which can produce cardiac arrhythmias (Paddleford, 1984). An anesthetic technique found effective in performing coronary stenting with good results in 32 pigs is discussed in this article.
  • Item
    Cerebral protection for the preclinical evaluation of a vascular graft in sheep carotid artery model
    (SCANDINAVIAN JOURNAL OF LABORATORY ANIMAL SCIENCE, 2015) Harikrishnan, VS; Umashankar, PR
    A protocol for cerebral protection without systemic hypothermia to aid the safe, smooth and fast recovery of sheep used for the preclinical evaluation of a, prosthetic vascular graft in the carotid artery is presented in this study. Ten adult Ramnad white sheep (33.8 +/- 3.2 kg) were green grass deprived and anticoagulated from 5 days prior to surgery with aspirin 150 mg and clopidogrel 75 mg till the end of the study. After anesthetic premedication and endotracheal intubation, the animals were ventilated at the rate of 12 breaths/min and tidal volume of 12 ml/kg. Ten minutes prior to carotid artery clamping (right unilateral internal carotid artery) which was performed after heparinisation, pharmacologic mitigation was done for cerebral protection with a total dose of thiopentone 50 mg (2.5%), 8 mg dexamethasone, 100 mg hydrocortisone and 15 ml (7.5% w/v) sodium bicarbonate as i/v bolus and 250 ml dextran 40 (10% w/v) at 40 ml/hour as i/v drip. Mean values of arterial pressure and heart rate were 94 +/- 16 mmHg and 88 +/- 11 min(-1) respectively, over the entire intra operative period. A moderate alkalosis which occurred in all animals under anaesthesia was postulated to supplement cerebral protection and was corrected by reducing the respiratory rate and tidal volume to 10 breaths/min and 10ml/kg respectively. Significant variation in pH (p<0.05) was observed at 90, 120, 150 and 180 minutes after induction of anaesthesia. Significant variation in MAP (p<0.05) was observed at 180 minutes after premedication, which was related to alkalosis and resultant hypokalemia and was effectively corrected with 31 +/- 7 meq potassium chloride (40 meq in 500 ml ringer lactate). The total procedure lasted 126 +/- 18 minutes and total unilateral right carotid arterial clamping time was 36.7 +/- 6.5 minutes. 28 +/- 5 minutes after spontaneous respiration, the animals were extubated and moved to the postoperative cage. Three doses of nadroparine 3800 IU s/c at 12 hour intervals were given postoperatively. All animals were free from any neurological deficits, which showed the effectiveness of the perioperative protocol encompassing the cerebral protective medication.
  • Item
    Cerebral protection for the preclinical evaluation of a vascular graft in sheep carotid artery model.
    (Scandinavian Journal of Laboratory Animal Science, 2016-08) Harikrishnan, VS; Umashankar, PR
    A protocol for cerebral protection without systemic hypothermia to aid the safe, smooth and fast recovery of sheep used for the preclinical evaluation of a prosthetic vascular graft in the carotid artery is presented in this study. Ten adult Ramnad white sheep (33.8± 3.2 kg) were green grass deprived and anticoagulated from 5 days prior to surgery with aspirin 150 mg and clopidogrel 75 mg till the end of the study. Aft er anesthetic premedication and endotracheal intubation, the animals were ventilated at the rate of 12 breaths/min and tidal volume of 12 ml/ kg. Ten minutes prior to carotid artery clamping (right unilateral internal carotid artery) which was performed aft er heparinisation, pharmacologic mitigation was done for cerebral protection with a total dose of thiopentone 50 mg (2.5%), 8 mg dexamethasone, 100 mg hydrocortisone and 15 ml (7.5% w/v) sodium bicarbonate as i/v bolus and 250 ml dextran 40 (10% w/v) at 40 ml/hour as i/v drip. Mean values of arterial pressure and heart rate were 94±16 mmHg and 88±11 min-1 respectively, over the entire intra operative period. A moderate alkalosis which occurred in all animals under anaesthesia was postulated to supplement cerebral protection and was corrected by reducing the respiratory rate and tidal volume to 10 breaths/min and 10ml/kg respectively. Signifi cant variation in pH (p<0.05) was observed at 90, 120, 150 and 180 minutes aft er induction of anaesthesia. Signifi cant variation in MAP (p<0.05) was observed at 180 minutes aft er premedication, which was related to alkalosis and resultant hypokalemia and was eff ectively corrected with 31±7 meq potassium chloride (40 meq in 500 ml ringer lactate). Th e total procedure lasted 126±18 minutes and total unilateral right carotid arterial clamping time was 36.7±6.5 minutes. 28±5 minutes aft er spontaneous respiration, the animals were extubated and moved to the postoperative cage. Th ree doses of nadroparine 3800 IU s/c at 12 hour intervals were given postoperatively. All animals were free from any neurological defi cits, which showed the eff ectiveness of the perioperative protocol encompassing the cerebral protective medication
  • Item
    A comparison of various methods of blood sampling in mice and rats: Effects on animal welfare
    (Laboratory Animals, 2018-06) Harikrishnan, VS; Hansen, AK; Abelson, KSP; Sørensen, DB
    This study was conducted to investigate the effects of blood sampling on animal welfare in a total of 60 NTac:SD rats and 72 C57BL/6NTac mice of both sexes. Blood was sampled either by sublingual vein puncture, tail vein puncture or by retrobulbar plexus/sinus puncture under light isoflurane anaesthesia and, additionally, by facial vein puncture in mice. Non-punctured animals as well as isoflurane-anaesthetised animals were used as controls. Pre- and post-puncture sucrose intake (1.5% w/w) was measured in rats, and nest building scores were studied in mice for 24 h post-puncture. Post-puncture activity and anxiety levels of rats and mice were measured using an elevated plus maze test and an open field test. Stress levels 24 h post-puncture were assessed by analysing faecal corticosteroid metabolites. Sucrose intake and faecal corticosteroid levels were not affected by the blood sampling procedures. Rats showed reduced activity in the open field test and an increased level of anxiety in the elevated plus maze test following retrobulbar plexus puncture and isoflurane anaesthesia. In mice, nest building activity was affected in all the groups compared with the control group, except for animals subjected to facial vein puncture. Retrobulbar sinus puncture, tail vein puncture and sublingual puncture in mice resulted in reduced activity and increased anxiety. We conclude that, of the tested methods, puncture of the tail vein and the sublingual vein have the least adverse effects in rats, whereas facial vein puncture had the least adverse effects on the welfare parameters in mice.
  • Item
    Contribution of fibroblasts to the mechanical stability of in vitro engineered dermal-like tissue through extra cellular matrix deposition
    (Bio Research Open Access, 2014-10) Nair, RP; Joseph, J; Harikrishnan, VS; Krishnan, VK; Krishnan, LK
    Tissue-engineered skin with mechanical and biological properties that match the native tissue could be a valuable graft to treat non-healing chronic wounds. Fibroblasts grown on a suitable biodegradable scaffold are a feasible strategy for the development of a dermal substitute above which epithelialization may occur naturally. Cell growth and phenotype maintenance are crucial to ensure the functional status of engineered tissue. In this study, an electrospun biodegradable polymer scaffold composed of a terpolymer PLGC [poly(lactide-glycolide- caprolactone)] with appropriate mechanical strength was used as a scaffold so that undesirable contraction of the wound could be prevented when it was implanted. To enhance cell growth, synthetic PLGC was incorporated with a fibrin-based biomimetic composite. The efficacy of the hybrid scaffold was evaluated by comparing it with bare PLGC in terms of fibroblast growth potential, extracellular matrix (ECM) deposition, polymer degradation, and mechanical strength. A significant increase was observed in fibroblast attachment, proliferation, and deposition of ECM proteins such as collagen and elastin in the hybrid scaffold. After growing fibroblasts for 20 d and 40 d, immunochemical staining of the decellularized scaffolds showed deposition of insoluble collagen and elastin on the hybrid scaffold but not on the bare scaffold. The loss of mechanical strength consequent to in vitro polymer degradation seemed to be balanced owing to the ECMdeposition. Thus, tensile strength and elongation were better when cells were grown on the hybrid scaffold rather than the bare samples immersed in culture medium. Similar patterns of in vivo and in vitro degradation were observed during subcutaneous implantation and fibroblast culture, respectively. We therefore postulate that a hybrid scaffold comprising PLGC and fibrin is a potential candidate for the engineering of dermal tissue to be used in the regeneration of chronic wounds.
  • Item
    Enriched adipose stem cell secretome as an effective therapeutic strategy for in vivo wound repair and angiogenesis.
    (3 Biotech, 2023-03) Ajit, A; Santhosh Kumar, TR; Harikrishnan, VS; Anil, A; Sabareeswaran, A; Krishnan, LK
    The therapeutic potential of adipose tissue-derived mesenchymal stem cells (ADMSCs) is well studied for use in non-healing wounds. However, concerns on the transplantable cell number requirement, cell expansion, cell viability, retained cell multipotency and the limited cell implantation time for efficient impact hinders cell therapy. Recent literature is much inclined to the superiority of the ADMSCs’ secretome, pre-dominating its paracrine-mediated therapeutic impact. In this context, the possibility of attaining accelerated wound angiogenesis through non-viral mediated enrichment of the ADMSCs secretome with pro-angiogenic growth factors (AGF) seems promising. Accordingly, this study aimed to explore the effect of AGF-enriched ADMSCs secretome for accelerating wound angiogenesis and repair in acute large area full thickness excision rabbit wound model, as adopted from Salgado et al. (Chir Buchar Rom 108:706–710, 1990). Using sub-dermal single-dose injections along the margin of the dorsal wound, native ADMSCs secretome, AGF-enriched ADMSC secretome, allogenic rabbit ADMSCs and a combination of AGF-enriched ADMSC secretome with allogenic rabbit ADMSCs were transplanted independently. Twenty-eight days (28 days) post-transplantation, histopathological analysis was performed to assess the effect. Hematoxylin and eosin (H&E) staining showed enhanced epithelization, notable granulation tissue and collagen fiber deposition in AGF-enriched secretome transplanted groups. This was confirmed by elevated CD31 detection, faster wound closure time and collagen organization. The use of single-dose AGF-enriched ADMSCs’ secretome for therapeutic angiogenesis and wound repair seems to be a promising cell-free therapeutic option. Further investigations using multiple doses on larger animal groups remains to be explored in order to ascertain the comparative potential of AGF-enriched ADMSCs’ secretome.
  • Item
    Exploring cadaver skin for standardization of rabbit and porcine burn models in research
    (Annals of Burn and Fire Disasters, 2020-12) Ajit, A; Krishnan, LK; Harikrishnan, VS; Varkey, P; Sabareeswaran, A
    Burn animal models provide substantial insights into burn pathophysiology. Choice of the apt model is important for determining the clinical efficacy of new medicines. Therefore, standardization of burn models is crucial for scientific research. Use of common techniques like hot water, electricity and incandescent instruments to generate animal burn models is widely reported. However, great discrepancy in employed temperature and exposure times demands user-dependent standardization of the animal model prior to research. Establishment of custom generated in vivo burn models giving consideration to reduced use, suffering and risk of the experimental animal is equally crucial. Accordingly, this pilot study demonstrates a novel approach using rabbit and porcine cadaver skin for standardization of burn parameters prior to use in live animal models. Using a custom-made soldering iron coupled to a 16cm2 surface area copper plate, burns at randomly chosen temperatures of 80˚C and 120˚C, with exposure times ranging from 60s to 180s, were produced on rabbit and porcine cadaver skins. On gross and histopathological analysis, parameters required to generate characteristic changes for deep partial and full thickness burn involvement were established. The identified temperature and exposure time parameters were further validated in live animal models. In vivo validation established the success of this approach, highlighting reduced animal use, ease, reproducibility and efficacy in burn model standardization. The findings of this study will hopefully encourage researchers to opt for cadaver skin to determine parameters required to generate a specific degree of burn prior to its use in live animals for burn research.
  • Item
    Extracellular matrix-based combination scaffold for guided regeneration of large-area full-thickness rabbit burn wounds upon a single application
    (Journal of Biomedical Material Research Part B Applied Biomaterials, 2021-11) Ramakrishnan, R; Harikrishnan, VS; Anil, A; Sabareeswaran, A; Krishnan, LK
    Regeneration of large acute and chronic wounds is a concern worldwide. The present study evaluates wound healing competence of a completely human-origin, extracellular matrix (ECM)-based skin substitute/graft. It comprises cell-less amniotic membrane (AM), clinical-grade fibrin (FIB), and hyaluronic acid (HA) termed as AMFIBHA. The use of large-area third-degree rabbit burn wounds evaluated the product efficiency. The AMFIBHA induces hemostasis and permits suture-less positioning on the wound bed. In wet wounds, the AMFIBHA degrades and release biologically active molecules and guide cell migration, proliferation, and regeneration. The study demonstrated the effectiveness of this wound care product in terms of epithelial-dermal regeneration with angiogenesis. The study assessed injury-associated inflammation and different wound healing markers after 28 days of experiment and compared with both positive and negative controls-treated wounds. The regeneration of mature epidermis and dermis with rete pegs and hair follicle-like structure was evident upon a single application. The active involvement of host cells resulted in supple tissue formation. The ECM organization of AMFIBHA-treated tissue resulted in re-gain of mechanical properties comparable to native skin after 56 days. These guided regenerative outcomes reveal a promising translational value of the novel AMFIBHA skin substitute as an off-the-shelf product for clinical use.
  • Item
    Human-Derived Scaffold Components and Stem Cells Creating Immunocompatible Dermal Tissue Ensuing Regulated Nonfibrotic Cellular Phenotypes
    (ACS Biomaterials Science & Engineering, 2020-04) Rashmi, R; Harikrishnan, VS; Arya, A; Sabareeswaran, A; Prashanth, V; Manesh, S; Lissy, KK
    Regeneration of large-sized acute and chronic wounds provoked by severe burns and diabetes is a major concern worldwide. The availability of immunocompatible matrix with a wide range of regenerative medical applications, more specifically, for nonhealing chronic wounds is an unmet clinical need. Extrapolating the in vitro tissue engineering knowledge for in vivo guided wound regeneration could be a meaningful approach. This study aimed to develop a completely human-derived and minimally immune-responsive scaffold comprising of acellular amniotic membrane (AM), fibrin (FIB) and hyaluronic acid (HA), termed AMFIBHA. The potential for in vivo guidance of skin regeneration was validated through in vitro dermal tissue assembly on the combination scaffold by growing human fibroblasts, differentiated from human adipose tissue-derived mesenchymal stem cells (hADMSCs). An effective method was standardized for obtaining decellularized amnion (dAM) for assuring better immuno-compatibility. The biochemical stability of dAM upon plasma sterilization (pdAM) confirms its suitability for both in vitro and in vivo tissue engineering. The problem of poor handling characteristics was solved by combining the dried dAM with fibrin derived from a clinically used fibrin sealant kit. An additional constituent HA, derived from human umbilical cord tissue, imparts the required water absorption and retention property for better cell migration and growth. Post sterilization, the combination scaffold AMFIBHA demonstrated hemo-/cytocompatibility, confirming the absence of detergent residuals. Upon long-term (20 days/40 days) culture of hADMSC-derived fibroblasts, the suppleness of generated tissue was established by demonstrating regulated deposition of collagen, elastin, and glycosaminoglycans using both qualitative and quantitative measurements. Regulated expressions of transforming growth factors-beta 1 (TGF-β1) & TGF-β3, alpha smooth muscle actin (α-SMA), fibrillin-1, collagen subtypes, and elastin suggest non-fibrotic fibroblast phenotype, which could be an effect of microenvironment endowed by the AM, FIB, and HA. In burn wound model experiments, immune response to cellular AM was prominent as compared to untreated/sham control wounds and decellularized AM-treated and AMFIBHA-treated wounds, ensuring biocompatibility. Wound regeneration with complete epithelialization, angiogenesis, development of rete pegs, and other skin appendages were clearly visualized in 28 days after treating large-sized (4 × 4 cm2), debrided, full-thickness third-degree burn wounds, indicating guided wound regeneration potential of AMFIBHA dermal substitute.
  • Item
    Incidence of Chirodiscoides caviae in Laboratory Rats-Screening, Identification and Treatment
    (SCANDINAVIAN JOURNAL OF LABORATORY ANIMAL SCIENCE, 2009) Harikrishnan, VS; Ranaraj, VR; Fernandez, AC
    This is a report on the incidence and treatment of the guinea pig fur mite Chirodiscoides caviae, which was so far considered as host specific, in a conventional colony of laboratory rats. Chirodiscoides caviae infestation in laboratory rats was accidentally observed during the screening of Syphacia obvelata by the peri-anal cellophane tape test (CTT). The organism was identified by comparing the morphology described by various researchers and was differentially diagnosed from other common mites of rat, Radfordia ensifera and Notoedres muris. The adult male mites (n=15) were of 330.2+/-13.3 mu m long and the females (n=15) 495.5+/-25.2 mu m. Later on, the entire rat colony consisting of Wistar, Sprague Dawley and Spontaneously Hypertensive Rats (SHR) and the mice colony of Balb/c and Swiss Albino were randomly sampled and screened for the presence of the mite by the cellophane tape technique. All the rat strains were found positive for C caviae infestation, which was more concentrated towards the posterior region of the body and, collectively, the screening results of C. caviae revealed that the posterio-dorsal and peri-anal regions are most suitable for sampling-suggesting that, the infestation pattern of C. caviae in rats has similarities to that of guinea pigs. Interestingly the mice colony was found free from the infestation. The Cellophane tape test was found to be an easier method than fur examination by hair plucking and equally accurate for screening of fur mite in a colony of laboratory rats. No clinical symptoms were observed in any of the animals in the colony, which possessed infestation. The facility strictly practised physical separation of animals by species, which pointed to the only possibility of cross infestation being through indirect contact between guinea pigs and laboratory rats and thereby questioning previous reports on the mode of transmission of C caviae. The entire colony was effectively treated with 0.2% lvermectin spray followed by 1% spray in an interval of 2 weeks. This report is the first one, which demonstrates the guinea pig fur mite in laboratory rats. It also questions the so far documented "host specificity" and "direct contact" mode of transmission and demonstrates indirect contact as a possible mode of transmission.
  • Item
    Ligand specific variation in cardiac response to stimulation of peroxisome proliferator-activated receptor-alpha in spontaneously hypertensive rat
    (MOLECULAR AND CELLULAR BIOCHEMISTRY, 2015) Ismael, S; Purushothaman, S; Harikrishnan, VS; Nair, RR
    Left ventricular hypertrophy (LVH) is an independent risk factor for cardiac failure. Reduction of LVH has beneficial effects on the heart. LVH is associated with shift in energy substrate preference from fatty acid to glucose, mediated by down regulation of peroxisome proliferator-activated receptor-alpha (PPAR-alpha). As long-term dependence on glucose can promote adverse cardiac remodeling, it was hypothesized that, prevention of metabolic shift by averting down regulation of PPAR-alpha can reduce cardiac remodeling in spontaneously hypertensive rat (SHR). Cardiac response to stimulation of PPAR-alpha presumably depends on the type of ligand used. Therefore, the study was carried out in SHR, using two different PPAR-alpha ligands. SHR were treated with either fenofibrate (100 mg/kg/day) or medium-chain triglyceride (MCT) Tricaprylin (5 % of diet) for 4 months. Expression of PPAR-alpha and medium-chain acylCoA dehydrogenase served as markers, for stimulation of PPAR-alpha. Both ligands stimulated PPAR-alpha. Decrease of blood pressure was observed only with fenofibrate. LVH was assessed from heart-weight/body weight ratio, histology and brain natriuretic peptide expression. As oxidative stress is linked with hypertrophy, serum and cardiac malondialdehyde and cardiac 3-nitrotyrosine levels were determined. Compared to untreated SHR, LVH and oxidative stress were lower on supplementation with MCT, but higher on treatment with fenofibrate. The observations indicate that reduction of blood pressure is not essentially accompanied by reduction of LVH, and that, progressive cardiac remodeling can be prevented with decrease in oxidative stress. Contrary to the notion that reactivation of PPAR-alpha is detrimental; the study substantiates that cardiac response to stimulation of PPAR-alpha is ligand specific.
  • Item
    Long duration anaesthesia for experimental surgical procedures in pigs.
    (INDIAN VETERINARY JOURNAL, 2006) Harikrishnan, VS; Umashankar, PR
  • Item
    Mechanically stable and functional dermal-like tissue generation on biodegradable PLGC-fibrin hybrid scaffold
    (BioResearch Open Access., 2015-01) Nair, RP; Joseph, J; Harikrishnan, VS; Kalliyanakrishnan, V; Krishnan, LK
    Tissue-engineered skin with mechanical and biological properties that match the native tissue could be a valuable graft to treat non-healing chronic wounds. Fibroblasts grown on a suitable biodegradable scaffold are a feasible strategy for the development of a dermal substitute above which epithelialization may occur naturally. Cell growth and phenotype maintenance are crucial to ensure the functional status of engineered tissue. In this study, an electrospun biodegradable polymer scaffold composed of a terpolymer PLGC [poly(lactide-glycolide-caprolactone)] with appropriate mechanical strength was used as a scaffold so that undesirable contraction of the wound could be prevented when it was implanted. To enhance cell growth, synthetic PLGC was incorporated with a fibrin-based biomimetic composite. The efficacy of the hybrid scaffold was evaluated by comparing it with bare PLGC in terms of fibroblast growth potential, extracellular matrix (ECM) deposition, polymer degradation, and mechanical strength. A significant increase was observed in fibroblast attachment, proliferation, and deposition of ECM proteins such as collagen and elastin in the hybrid scaffold. After growing fibroblasts for 20 d and 40 d, immunochemical staining of the decellularized scaffolds showed deposition of insoluble collagen and elastin on the hybrid scaffold but not on the bare scaffold. The loss of mechanical strength consequent to in vitro polymer degradation seemed to be balanced owing to the ECM deposition. Thus, tensile strength and elongation were better when cells were grown on the hybrid scaffold rather than the bare samples immersed in culture medium. Similar patterns of in vivo and in vitro degradation were observed during subcutaneous implantation and fibroblast culture, respectively. We therefore postulate that a hybrid scaffold comprising PLGC and fibrin is a potential candidate for the engineering of dermal tissue to be used in the regeneration of chronic wounds.
  • Item
    A novel technique to develop thoracic spinal laminectomy and a methodology to assess the functionality and welfare of the contusion spinal cord injury (SCI) rat model.
    (PLOS ONE, 2019-07) Harikrishnan, VS; Krishnan, LK; Abelson, KSP
    This study reports the advantage of a novel technique employing a motorised dental burr to assist laminectomy over the conventional manual technique at T10-T11 vertebra level in a rat model of spinal cord injury. Twenty-four female rats were randomly assigned to four groups: (1) conventionally laminectomised, (2) dental burr assisted laminectomised, (3) conventionally laminectomised with spinal cord contusion and (4) dental burr assisted laminectomised with spinal cord contusion. Basso Beattie Bresnahan (BBB) score, postoperative body weights, rat grimace scale (RGS), open cage activity and rearing was studied at 1, 7, 14, 21 and 28 days postoperatively, and area of spinal tissue affected was evaluated histologically. Laminectomised and spinal cord injured rats from dental burr groups showed significantly more weight gain and less weight loss respectively in comparison with respective conventionally laminectomised groups at various time points. Significantly higher RGS score was noticed in conventionally laminectomised animals on Day 1 in comparison to burr assisted laminectomy and presence of pain was evident until Day 7 in the conventionally spinal cord injured group. BBB score did not differ between techniques, whereas laminectomy groups showed more resting time than spinal injury groups. High rearing score was significantly higher in groups which underwent dental burr assisted technique at various time points with respect to their conventional counterparts. This study suggests that the use of dental burr assisted technique to perform laminectomy will bring refinement by producing less pain, aiding in better recovery, removing procedural artefacts without affecting the outcome of the model.
  • Item
    Orchidectomy Reduced Abdominal Aorta Relaxation Response to Androgens in Sprague Dawley Rats Fed a High Salt Diet
    (FASEB JOURNAL, 2010) Oloyo, AK; Sofola, OA; Nair, R; Harikrishnan, VS; Fernandez, AC
  • Item
    Rabbit Snake-Bite Model to Assess Safety and Efficacy of Anti Viper Chicken Antibodies (IgY)
    (American Journal of Clinical and Experimental Medicine, 2015-04) Krishnan, LK; Saroja, JB; Rajalingam, M; John, V; Mohanan, PV; Harikrishnan, VS
    Infusion of mammalian antivenom is considered to be the best available treatment for snake bites; but, production of cost-effective IgG in pure form is challenging. Purification of egg yolk immunoglobulins (IgY) raised against various toxins has been found to be relatively easier. But to use IgY for therapeutic purpose its efficacy and safety need to be experimentally proven which is hardly done due to lack of an appropriate model. In this study, pure IgY against viper venom was isolated and its efficacy and safety for intravenous infusion was tested in rabbits. Rabbit snake bite model was created by subcutaneous injection of 2x lethal dose50 (LD50) venom. Animals were given intravenous infusion of pure anti-viper IgY and recovery was monitored. Isolated chicken immunoglobulin (IgY) was >90% homogenous and showed 1:32 titre in immunodiffusion experiment. The minimum hemorrhagic dose (MHD) of viper venom was 0.2mg and antihaemorragic dose (AHD) of IgY was 4x concentration (0.8 mg) of native venom. Subcutaneously injected venom at LD50 resulted in severe local reaction, coagulation abnormality and mortality in rabbits. When anti viper IgY was infused within 2 h of envenomation, the animals survived, clotting parameters were reversed to normal and animals showed steady weight gain like healthy animals. No adverse effect of IgY was noticed on renal or hepatic function. The efficacy of commercially available mammalian IgG was lower than that of anti-viper IgY. Long term stability of the purified and lyophilized IgY was demonstrated. The effective IgY dose required to prevent mortality in the envenomed rabbits was found to be 4x of the injected venom estimated by Lowry’s protein assay. It has been demonstrated that rabbit model of snake bite is successfully cured by anti-snake IgY infusion at a specific dose.
  • Item
    Refinement of the spinal cord injury rat model and validation of its applicability as a model for memory loss and chronic pain
    (Heliyon, 2021-07) Harikrishnan, VS; Palekkodan, H; Fasaluddeen, A; Krishnan, LK; Abelson, KSP
    Background Laminectomy produces trauma in spinal cord injury (SCI) animal models resulting in impinging artefacts and welfare issues. Mechanizing laminectomy using a dental burr assisted (DBA) technique to reduce the impact of conventionally performed laminectomy on animal welfare without any alterations in the outcome of the model was previously demonstrated. However, further validation was necessary to establish it as an alternative in developing SCI rats as a model of chronic pain and memory loss. Novel method DBA technique was employed to perform laminectomy at T10-T11 vertebrae in rats undergoing contusion SCI as a model of chronic pain and memory loss. In a 56-day study, 24 female Wistar rats (Crl: WI) were assigned randomly to four equal groups: conventionally laminectomised, DBA laminectomised, conventionally laminectomised with SCI and DBA laminectomised with SCI. Results The study revealed DBA technique to cause less surgical bleeding (p = 0.001), lower Rat Grimace Scale (p = 0.0006); resulted in better body weight changes (p = 0.0002 on Day 7 and p = 0.0108 on Day 28) and dark phase activity (p = .0.0014 on Day 1; p = 0.0422 on Day 56). Different techniques did not differ in Basso Beattie Bresnahan score, novel object recognition, mechanical allodynia, number of surviving neurons and the area of vacuolation- indicating that the new method doesn’t affect the validity of the model. Comparison with existing method(s) In comparison with the conventional technique, motorised laminectomy can be a valid tool that evokes lesser pain and ensures higher well-being in rats modelled for chronic pain and memory loss. Conclusions The intended outcome from the model is not influenced by techniques whereas the DBA-technique is a refined alternative to the conventional method in achieving better welfare in SCI studies.
  • Item
    Stem Cell Derived Exosome Therapy for Clinical Management of Lung Damage in Critically-ill Corona Viral Pneumonia Patients ( Project - 8194 )
    (SCTIMST, 2021-12-30) Naresh, Kasoju; Senthilkumar, Mutusamy; Harikrishnan, VS; Sabareeswaran, A; Anil Kumar, PR; Francis B, Fernandez
  • Item
    Tissue-engineered ceramic for promoting osteointegration in osteoporotic animal models with relevance to the clinical problem in women ( Project - 8103 )
    (SCTIMST, 2018-05-13) Annie, John; Harikrishna Varma, PR; Sachin J, Shenoy; Harikrishnan, VS