Toxic effects of cypermethrin and methamidophos on bovine corpus luteal cells and progesterone production.

This study was planned and executed with the aims to explore corpus luteal primary cell culture as an "animal alternate testing system" in toxicity studies and in vitro toxic effects of cypermethrin (CY) 90% (pyrethroid) and methamidophos (MTP) 73% (organophosphate) on morphology and progesterone secretory activity of bovine corpus luteal cells and tissue. For this purpose, primary cell cultures of bovine corpus luteum (CL) cells were maintained in Dulbecco's Modified Eagle Medium (DMEM) supplemented with 5% fetal calf serum (FCS). Toxicity evaluation were based on viable CL cell counts, morphological changes in CL cells, ability of CL cells to produce progesterone and histological changes in CL tissue at different hours post exposure to CY and MTP. The changes induced by both the insecticides were time and dose dependant. Viable cell counts and progesterone concentration decreased significantly (P<0.05) with the treatment of CY and MTP when compared to control. Corpus luteal cells exposed to CY showed more severe toxic effects as compared to MTP, though the difference was non-significant. Cellular or tissue alterations included degenerative changes in luteal cells, pleomorphic changes, nuclear degeneration and vacuolation, cell shrinkage and rupture, cloudy swelling and hydropic degeneration, less cytoplasmic granulation, cell elongation, hyalinization and cytoplasmic haziness and stripling and necrosis. It was concluded that both the insecticides induce toxic effects in terms of viable counts, morphological and histological changes and progesterone production of bovine CL cells. Cypermethrin exhibited more adverse toxic changes in viable cell counts, progesterone production and histological findings as compared to methamidophos.