Modulation of Gamma Ray–Induced Genotoxic Effect by Thymol, a Monoterpene Phenol Derivative of Cymene

Archana, PR and Rao, Nageshwar B and Rao, Satish BS (2011) Modulation of Gamma Ray–Induced Genotoxic Effect by Thymol, a Monoterpene Phenol Derivative of Cymene. Integrative Cancer Therapies, 10 (4). pp. 374-383.

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The radioprotective effect of thymol (TOH), a monoterpene phenol, on radiation-induced DNA damage was analyzed in vitro. Chinese hamster lung fibroblast cells (V79) were treated with different concentrations of TOH (0-100 µg/mL) for 1 hour before exposure to 3 Gy gamma irradiation, and then cytokinesis-blocked micronucleus and single-cell gel electrophoresis (comet assay) assays were used to evaluate the radiation-induced cytogenetic damage and genotoxic effects. Furthermore, the modulating effect of TOH on radiation-induced cell death was assessed by apoptotic and necrotic cell detection by staining with ethidium bromide/acridine orange using fluorescence microscopy. To understand the mechanism of TOH-imparted cytoprotection, mitochondrial membrane potential (MMP) was detected by flow cytometry after staining the cells with Rhodamine 123. Pretreatment of V79 cells with various concentrations of TOH (0-100 µg/mL) for 1 hour reduced the radiation-induced micronuclei as well as percent tail DNA and mean Olive tail moment with a maximum protective effect observed at TOH (25 µg/mL). Apoptosis by microscopic, MMP measurements indicated that the V79 cells exposed to gamma radiation alone showed a maximal increase in the number of early and late apoptotic and necrotic cell death associated with a significant loss of the MMP. Pretreatment with TOH (25 µg/mL) showed a significant (P < .01) decrease in the level of apoptotic fraction as well as necrotic cells and suppressed the radiation-induced collapse of MMP when compared with the radiation alone group. These results suggest that TOH suppresses radiation-induced genotoxicity, apoptosis, and necrosis primarily by the free radical scavenging and modulation of oxidative stress.

Item Type: Article
Uncontrolled Keywords: apoptosis, comet assay, micronucleus assay, mitochondrial membrane potential, radiation, thymol
Subjects: Life Sciences > MLSC Manipal
Medicine > KMC Manipal > Neurology
Medicine > KMC Manipal > Physiology
Depositing User: KMC Manipal
Date Deposited: 01 Aug 2012 09:40
Last Modified: 01 Aug 2012 09:40

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