Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Zoology

Pesticides exposure has been proved to be associated with elevated risk of genotoxicity and carcinogenicity. Previous studies have indicated that genetic polymorphism in GSTP1 gene that encoded proteins involved metabolism/detoxification may modulate pesticides metabolism. On the other hands, genetic polymorphism in XRCC gene that encoded proteins involved in DNA repair process may influence pesticides genotoxicity. Thus, we investigated whether various metabolic (GSTP1) and DNA repair (XRCC1) genotypes could increase the risk of DNA damage and oxidative stress in pesticides-exposed agricultural workers. The different genotypes of studied genes were identified by PCRRFLP technique. The DNA damage was estimated using comet assay. Moreover, oxidative stress and antioxidant status of pesticides-exposed agricultural workers were evaluated relative to control subjects. In this study, measurement of cholinesterase activity was used as a biomarker for pesticides exposure. The results of the present work showed that individuals carrying GSTP1 Ile-Ile or XRCC1 399 Arg-Arg genotypes are more susceptible to DNA damage and could be at high risk of cancer. Moreover, there was an alteration in antioxidant status and significant increase in oxidative stress biomarker (MDA) in pesticides-exposed agricultural workers compared to unexposed controls. In addition, there was positive correlation between oxidative stress marker (MDA) and DNA damage. In conclusion, our study indicated that polymorphism in GSTP1 and XRCC1 genes could modulate extent of DNA damage caused by pesticides exposure. The susceptible workers agricultural workers who are involved in pesticides handling should be provided with more protective equipments in order to reduce the potential hazard of occupational exposure to these carcinogenic agents

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