Allethrin induces oxidative stress, apoptosis and calcium release in rat testicular carcinoma cells (LC540)

Over the years, pyrethroids, including D-allethrin, are widely used for domestic and agricultural purposes and are found to be toxic to many organ systems including the male reproductive system. However, the molecular mechanisms of allethrin toxicity are not well understood. In this study, we demonstrate that allethrin exhibited a dose-dependent cytotoxicity on Leydig cell carcinoma cells (LC540) and isolated primary Leydig cells with an IC50 of 125 μM and 59 μM respectively. Cytotoxicity was associated with generation of reactive oxygen species, increased lipid peroxidation and alterations in antioxidant enzyme status. Morphological analyses of LC540 cells treated with allethrin revealed the presence of apoptotic bodies. Using flow cytometry, we observed that the number of cells that displayed early apoptotic features and entering into G0 phase of cell cycle increased significantly with loss of mitochondrial membrane potential. The levels of p53 mRNA and cleaved PARP-1 protein were increased, whereas BCL-2, pro-Caspase-3 and PARP-1 were decreased. Allethrin induced apoptosis was associated with voltage gated calcium channel mediated intracellular calcium release. Results of our study demonstrate that allethrin toxicity in the male reproductive tract may involve Leydig cell apoptotic death.