Coridius chinensis Extract Promotes Leydig Cell Endocrine Function Rescuing Testosterone Deficiency and Sexual Behavior Insufficiency in Manganese-Exposed Rat

Coridius chinensis is a traditional Chinese medicinal insect, whose extract (CcE) is widely used for male reproductive disorders. Manganese (Mn²⁺) as a heavy metal pollutant can cause toxicity to the reproductive system in mammals. Previous studies found that CcE can resist the apoptosis and oxidation by Mn²⁺ exposed to repair the damage of seminiferous epithelium in rat. However, the therapeutic effect of CcE in the testicular stroma remains unclear. Our study found that the slow mating behaviors of capture, riding, insertion, and ejaculation with Mn²⁺ exposure were improved by CcE treatment in male rat. The level of testosterone was significantly increased in CcE-treated groups. Meanwhile, the damage about less area and cell number in testicular stroma due to Mn²⁺ exposure was repaired after CcE treatment. Ultrastructure analysis of Leydig cells showed the larger mitochondria and more endoplasmic reticulum in Mn²⁺CcE groups became than that in Mn²⁺ group. Further experiments showed that mRNA and protein level of steroidogenic-related regulators (STAR, CYP11α1, and HSD3β1) were significantly decreased in Mn²⁺ group and strongly upregulated occurred at medium concentration of CcE given. Taken together, our results provide a new insight of CcE in promoting testosterone production of Leydig cells to protect male reproductive behavior from Mn²⁺ toxicity.