Gossypol, commonly found in cotton seeds, is hazardous to male reproductive physiology. Although several studies have indicated the toxicity of gossypol in human and animal reproduction, the mechanism of gossypol action in testes has not yet been elucidated. In the present study, we investigated the effects of gossypol in normal mouse testis cells, TM3 and TM4 cells, and in gossypol-treated C57BL/6 mice. We confirmed the antiproliferative effects of gossypol using cell viability assays, with PCNA as a proliferation marker, and cell cycle analysis. We also verified mitochondrial dysfunction and Ca2+ dysregulation in the cytosol of TM3 and TM4 cells, using JC-1 and Fluo-4 dyes. To confirm the cellular signaling mechanisms in testis cell lines, we performed Western blot analysis to assess the changes in MAPK and PI3K/Akt signal transduction, using their pharmacological inhibitors. Moreover, we screened the mRNA expression of genes involved in spermatogenesis and steroidogenesis in TM3 and TM4 cells. We also confirmed the mRNA expression and localization of genes regulating testis function in gossypol-treated and untreated mice testes. Collectively, we suggest that gossypol induces negative effects on testis function by reducing cell viability, mitochondrial membrane potential, and testis development-related genes in vitro and in vivo as well as by modulating the MAPK and PI3K signaling pathways.
Keywords: gossypol; mitochondrial dysfunction; spermatogenesis; steroidogenesis; testis.