Toxicity of methomyl insecticides to testicular cells and protective effect of folic acid.

Methomyl is a carbamate insecticide with confirmed testicular toxicity. This study intended to observe the effect of methomyl on testicular cells and the protective effect of folic acid through in vitro experiments. The GC-1 spermatogonia, TM4 Sertoli cells, and TM3 Leydig cells were treated with methomyl (0, 250, 500, and 1000 μM) with or without folic acid (0, 10, 100, and 1000 nM) for 24 h. It was found that methomyl increased cytotoxicity to testicular cells in a dose-dependent manner. In spermatogonia, methomyl significantly inhibited the expression of proliferation genes Ki67 and PCNA at 1000 μM, and increased the expression of apoptosis genes Caspase3 and Bax at each dose. In Sertoli cells, methomyl dose-dependently inhibited the expression of blood-testis barrier function genes TJP1, Cx43, and N-cadherin, but did not affect Occludin and E-cadherin. In Leydig cells, methomyl inhibited the expression of steroid synthase P450scc, StAR, Hsd3b1 and down-regulated the level of testosterone, but did not affect Cyp17a1 and Hsd17b1. Further, folic acid could basically reduce the damage caused by methomyl. This study provided new insights into the toxicity of methomyl and the protective effect of folic acid.