ROS accumulation contributes to abamectin-induced apoptosis and autophagy via the inactivation of PI3K/AKT/mTOR pathway in TM3 Leydig cells.

Abamectin (ABA) as one of the worldwide used compounds in agriculture has raised safety concerns on nontarget organism toxicity. However, the study of male reproductive system damage caused by ABA remains unclear. Our aim is to investigate the effect of ABA-induced cytotoxicity in TM3 Leydig cells and their underlying mechanisms. ABA inhibits TM3 cell viability and proliferation via cell cycle arrested in the G0/G1 phase. In addition, ABA-induced mitochondrial depolarization leads to an imbalance in Bcl-2 family expression, causing caspase-dependent apoptosis in TM3 cells. The increased ratio of cells expression LC3 protein and LC3-II to LC3-I indicated the activation of autophagy potentially. Further experiments revealed ABA treatment reduced phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT) phosphorylation, and mammalian target of rapamycin (mTOR) phosphorylation. Pretreatment with a PI3K/AKT inhibitor, LY294002, mimicked the ABA-mediated effects on cytotoxicity. Pretreatment with a PI3K/AKT agonist, insulin-like growth factor-1, reversed the effects of ABA. ABA caused the accumulation of intracellular reactive oxygen species (ROS) by increased intensity of the ROS indicator. However, N-acetylcysteine as ROS scavengers inhibited ABA-induced apoptosis and autophagy and reversed these ABA-mediated effects on PI3K/AKT/mTOR pathway. On the basis of the above results, it is suggested that ABA exposure induces apoptosis and autophagy in TM3 cells by ROS accumulation to mediate PI3K/AKT/mTOR signaling pathway suppression.