Effect of Imidacloprid- A Neonicotinoid Insecticide on Reproductive Functions of Female Rats
Abstract
Imidacloprid, a neonicotinoid insecticide is widely and most commonly used insecticide in soil, seed and
foliar application for the control of suckling insects including rice hoppers, aphids, whiteflies, termites, turf insects,
soil insects and some beetles and as an ectoparasiticide in veterinary medicine, Yet its effects on reproductive
system of nontarget mammals have not been studied extensively. Study to assess the effects of imidacloprid on
reproductive system was carried out in female wistar rats at two dose levels (19 and 38 mg/kg/day) administered for
10, 20 and 30 days. Effects were compared with respective control animals administerd daily with 2% gum acasia
(1ml/100g b.wt.) for 10, 20 and 30 days. Different parameters undertaken were body weight, body organ weight,
oxidative stress parameters viz. antioxidant enzymes (superoxide dismutase (SOD), glutathione peroxidase (GPx)),
reduced glutathione (GSH), and the lipid peroxidation (LPO) product malondialdehyde (MDA), cytoplasmic and
membrane proteins in different organs (liver, kidney, ovary, uterus) and blood, microelements (zinc, copper and
iron) level in ovary, progesterone level in plasma, and histopathological changes of vital organs.
Imidacloprid at 38 mg/kg dose administered daily for 10, 20 and 30 days significantly increased levels of
MDA and relative organ weights of liver and kidney after 20 and 30 days post administration. In ovary and plasma
increased levels of MDA was observed at 38 mg/kg dose administered for 30 days. There was significant decrease in
level of SOD enzyme in liver, ovary, uterus and in red blood cells at 38 mg/kg dose of imidacloprid administered
daily for 20 and 30 days; GSH level was decreased in red blood cells; GPx enzyme levels were decreased in liver
and ovary; and cytoplasmic and membrane proteins were decreased in liver and kidney tissues. At 38 mg/kg dose of
imidacloprid administered daily for 30 days there was significant decrease in SOD enzyme level in kidney; GSH
levels in both liver and kidney, GPx enzyme level in kidney and uterus. Cytoplasmic and membrane proteins were
decreased in kidney, uterus, ovary and in red blood cells. No significant change in level of copper and iron was
observed at both the doses. Zinc level was significantly increased in ovaries and serum progesterone level was
decreased at 38 mg/kg dose administered daily for 30 days. Histopathological changes were observed in liver,
kidney and ovary at 38 mg/kg dose administered daily for 20 and 30 days. Histopathological changes in uterus were
observed at 38 mg/kg dose administered daily for 30 days. No significant changes were observed at 19 mg/kg dose
of imidacloprid administered daily for 10, 20 and 30 days.