The oxidative stress and neurotoxicity potential of diazinon in the tissuse of cyprinus carpio

ABSTRACT MSc THESIS THE OXIDATIVE STRESS and NEUROTOXICITY POTENTIAL of DIAZINON in the TISSUES of Cyprinus carpio Demet USTA UNIVERSITY OF ÇUKUROVA INSTITUTE OF NATURAL AND APPLIED SCIENCES DEPARTMENT OF BIOLOGY Supervisor: Assist.Prof.Dr. Elif ORUÇ Year: 2003, Page: 99 Jury: Assist.Prof.Dr. Elif ORUÇ Prof.Dr. Nevin ÜNER Assoc.Prof.Dr. LüHifer TAMER Tissue-specific defenses against the possibility of oxidative stres and lipid peroxidation were compared in adult fish, Cyprinus carpio exposed to diazinon for 5, 15 and 30 days. We also examined the alterations of acetylcholinesterase and sodium potassium adenosine triphosphatase specific activities in order to evaluate the neurotoxic potential of diazinon and its effect on ion transmission in the different tissues offish after diazinon exposure, by using spectrophotometric methods. 0.0036 ppb, 0.018 ppb and 0.036 ppb were chosen as experimental concentrations based on the environmental levels and lethal concentration of pesticide in C. carpio. Diazinon exposure caused the neurotoxicity in gill and muscle tissues, however no changes observed in gastrointestinal tract and kidney tissue. A significant decline was recorded in sodium potassium adenosine triphosphatase activity in muscle and kidney tissues while fluctuation was shown in gill. Superoxide dismutase activity increased against to oxidative stress depending on diazinon toxicity in all tissues with the exception of gastrointestinal tract. There is no significant changes in glutathione peroxidase activity in gastrointestinal tract and kidney tissue while the activity tends to increase in gill and muscle tissues. Catalase activity decreased in gastrointestinal tract and muscle tissues whereas no significant alteration was observed in gill and kidney tissues. Malondialdehyde content increased in response to diazinon treatment in all tissues except for kidney in which decreasing and increasing trends were recorded. Protein content declined in a concentration-dependent manner only in gill for 5 days. According to the findings of the present study, sublethal diazinon concentrations may cause oxidative stress and neurotoxicty, and induce tissue specific responsse in C. carpio dose dependently. Furthermore, superoxide dismutase may be used as a bioindicator of diazinon toxicity. Key words: Diazinon, C. carpio, oxidative stress, AChE, Na^^ATPase II