Lead Acetate Induces Apoptosis In Leydig Cells By Activating Ppar Gamma/Caspase-3/Parp Pathway

This study was designed to investigate the cytotoxicity of lead acetate (Pb(AC)(2), a representative air pollutant) by focusing on PPAR gamma/caspase-3/PARP apoptotic signaling pathway and to explore the inhibitory effect of PPAR gamma antagonist on apoptosis of TM3 Leydig cells. MTT assay was utilized to examine cell viability. Cell apoptosis was analyzed using a flow cytometry by staining with Annexin V-PE/7AAD staining and a fluorescence microscope by staining with Hoechst 33,258. The levels of apoptosis-related proteins were examined using western blot. From the results, Pb reduced significantly TM3 cell proliferation in concentration- and time-dependent manner. It increased significantly apoptosis; increased the PPAR gamma, Bax, procaspase-3, cleaved caspase-3, proPARP, cleaved PARP levels; and decreased Bcl-2 level in Pb-treated TM3 cells as compared to control cells. Furthermore, pretreatment with PPAR gamma antagonist significantly attenuated the apoptosis and cleavage of caspase-3 and PARP induced by Pb. Our results suggested that Pb induced cytotoxicity on TM3 Leydig cells, at least in part, by increasing PPAR gamma expression, stimulating cleavage of caspase-3 and PARP, and then induced cell apoptosis.