Effects of Hexachlorocyclohexane (HCH-γ-Isomer, Lindane) on the Reproductive System of Zebrafish (Danio rerio)

In this study, histopathological changes induced by lindane a gamma isomer of hexachlorocyclohexane and its intoxication associated with reproductive system and hormone levels were investigated in zebrafish. In all, 320 zebrafish adults approximately 1 year in age, (Danio rerio) obtained from a commercial entity were used in the study. Zebrafish were divided into 8 groups, each one containing 40 zebrafish. Groups were organized as 0 (the control group), 1 ml/L methanol, and 5, 10, 20, 40, 80, 160 mu g/L/day lindane. In the study, the gamma-HCH-isomer was applied at rates of 5/10/20/40/80/160 mu g/L/day as doses of immersion to each group for 21 days. Macroscopically, the drop in egg production was observed, especially in the 80 and 160 mu g/L/day groups of female zebrafish. A microscopic decrease in ovulation and biochemical decreases in estradiol (E-2) levels (40/80/160 mu g/L) were also observed in the female zebrafish. As a result, lindane was found to cause changes in the reproductive system, and consequently, to cause hormonal disorders and to have significant effects on ovulation and fertilization in the female zebrafish.