Browsing by Author "Tinu, SK"

Now showing 1 - 4 of 4
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    Analysis of mitochondrial DNA damage using 8-hydroxy 2 ' deoxyguanosine on in vitro and in vivo exposure of biomaterials
    (TOXICOLOGY MECHANISMS AND METHODS, 2013) Tinu, SK; Vaman, VSA; Geetha, CS; Mohanan, PV
    The present study was carried out to evaluate the effect of HAP-EVA, fibrin glue, HA-BG, Latex and Dental material on oxidative stress related mtDNA damage by in vitro and in vivo methods. In vivo studies of these biomaterials were carried out by implanting biomaterials (five materials) on animals for period of 1, 4, 12, 26 and 52 weeks. At the end of observations, animals were anesthetized, sacrificed and tissues surrounding the implanted materials were collected. Brain, bone and muscles were used for the extraction of mtDNA. Similarly mtDNA was extracted from the homogenate of fresh brain, bone and muscles on exposure to the physiological saline extract of all the above five biomaterials (In vitro). The extracted mtDNA were subjected to analyse the presence of 8-OHdG. The results of study indicated that there was no significant increase in the level of 8-OHdG and thereby does not influence on the GC-TA transversions.
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    Assessment of micronuclei and chromosomal anomalies of five biocompatible materials in mice
    (TOXICOLOGICAL AND ENVIRONMENTAL CHEMISTRY, 2012) Vaman, VSA; Tinu, SK; Geetha, CS; Mohanan, PV
    In vivo genetic toxicology tests measure direct DNA damage or the formation of gene or chromosomal mutations, and are used to predict mutagenic and carcinogenic potential of compounds for regulatory purposes. These adverse genotoxic effects may be manifested in the form of gene mutations, structural chromosomal aberrations (CA), recombination, and numerical changes. The present investigation was carried to assess genotoxic effects of five different implantable biomaterials developed in different laborataries of Sree Chitra Tirunal Institute of Medical Sciences and Technology. All biomaterials were developed for clinical applications. CA and micronuclei (MN) studies are biomarkers of genotoxicity testing. Leachants from the extract of biomaterials are capable of inducing structural and numerical chromosomal changes. The studies were conducted in Swiss albino mice with the physiological saline extract of materials together with cyclophosphamide and physiological saline as positive and negative controls. Animals were administered intraperitoneally (ip) with a single injection of test, positive (cyclophosphamide), and negative (physiological saline) control and sacrificed after 24 or 48 h. Bone marrow cells were collected for CA and MN assays. Data showed that all five biomaterials did not significantly exert genotoxic effects. Hence, the study indicates that these biomaterials do not induce any chromosomal anomalies.
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    Effect of fibrin glue on antioxidant defense mechanism, oxidative DNA damage and chromosomal aberrations
    (TOXICOLOGY MECHANISMS AND METHODS, 2013) Vaman, VSA; Tinu, SK; Geetha, CS; Lissy, KK; Mohanan, PV
    Oxidative stress is involved in diverse biological phenomenon, and is caused by the imbalance between reactive oxygen species (ROS) and antioxidant defense system. 8-Hydroxy-20-deoxyguanosine (8-OHdG) is the most critical biomarker in the estimation of ROS-induced DNA damage. This investigation focuses on the effect of fibrin glue on lipid peroxidation (LPO), antioxidant enzymes and oxidative DNA damage (both in vitro and in vivo). The blood biochemical parameters of the implanted animals and in vitro chromosomal aberrations were also studied. Fibrin glue was applied on the calvarial defect made on the anesthetized rats for an observation period of 4, 12, 26 and 52 weeks. At the end of the observation period, animals were anesthetized; blood was collected for serum analysis and was sacrificed. Brain was collected for the detection of 8-OHdG using competitive ELISA and liver was collected for analyzing the antioxidant enzymes and LPO. The results of this study suggest that the effect of fibrin glue on rat brain (in vivo and in vitro) and mice liver (in vitro) did not make any significant influence on LPO and antioxidant defense system. Similarly, there was no change observed in the expression of 8-OHdG. Serum constituents of implanted rats were observed to be within the normal range. The normal karyotype obtained indicates that the physiological saline extract of fibrin glue does not induce any chromosomal anomalies. Hence, it was concluded that the fibrin glue material does not have any potential to produce oxidative stress, alterations in the C-8 position of guanine and chromosomal anomalies.
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    Effect of latex material on antioxidant enzymes, lipid peroxidation, DNA damage, and chromosomal aberration
    (TOXICOLOGICAL AND ENVIRONMENTAL CHEMISTRY, 2012) Tinu, SK; Vaman, VSA; Arun, M; Geetha, CS; Mohanan, PV
    Cell integrity is affected by oxidative stress when the production of active oxidants overwhelms antioxidant defense mechanisms. Latex, a natural polymer obtained from Hevea brasiliensis, is used in medical industry for manufacturing surgical gloves, urinary catheters, and dental dams. The aim of this study was to evaluate the effects of latex material on oxidative stress by in vivo and in vitro methods. In addition, the material was screened for its ability to induce any chromosomal aberrations (CAs) by in vitro method. In vivo studies were carried out with implanted latex material onto subcutaneous tissue of various batches of experimental Wistar rats. At the end of experimental period, animals were anesthetized, blood was collected for serum analysis, and sacrificed. Liver was excised for the determination of antioxidant enzymes and lipid peroxidation (LPO). Subcutaneous tissues were obtained for the extraction of genomic DNA from implanted animals and checked for the presence of 8-hydroxy-2-deoxyguanosine (8-OHdG), considered an indicator of DNA damage. Simultaneously, in vitro studies were carried out using fresh liver and subcutaneous tissue obtained from Swiss albino mice treated with physiological saline extract of latex material. For the estimation of both in vitro and in vivo oxidative stress, 10% liver homogenate was assessed for stress indicators like reduced glutathione, glutathione reductase, glutathione peroxidase, LPO and protein content. The results of both in vivo and in vitro studies indicated that the chemical leachents from the latex material did not significantly affect LPO and the levels of antioxidant enzymes. There was also no significant increase in 8-OHdG content due to the presence of implanted latex material. Finally, the results of in vitro CA test and G banding indicated that extracts of test material did not induce any chromosomal abnormalities.