CHANGES IN RAT THYMUS MORPHOLOGY AND FUNCTION AFTER CHRONIC EXPOSURE TO LOW DOSES OF DDT

There is increasing evidence that chronic environmental exposure to DDT and other pesticides play an important role in disregulation of the immune system and increased incidence of autoimmune and allergic diseases. The aim of the research was to investigate whether consumption of low doses of DDT may affect the immune system and change morphology and function of thymus. The research was performed on 42 Wistar rats 80-100gg body weight. Rats were exposed to 1.89±0.086μg/kg DDT per os for 6 and 10 weeks. Histological examination found time-depending acceleration of apoptosis both of lymphocytes and reticuloepitelial cells. After 10 weeks of exposure proliferation of thymocytes was significantly decreased. Concanavalin A-induced mitogenic activity of thymocytes after 10 weeks of exposure to DDT was 6 times higher than the control values. The data obtained showed that even low doses of DDT accelerated thymus aging and modulated proliferation of thymocytes.