Wuzi-Yanzong prescription alleviates spermatogenesis disorder induced by heat stress dependent on Akt, NF-κB signaling pathway

Akt and nuclear factor kappa B (NF-κB) signaling pathways are involved in germ cell apoptosis and inflammation after testicular heat stress (THS). We observed that after THS induced by the exposure of rat testes to 43 °C for 20 min, their weight decreased, the fraction of apoptotic testicular germ cells significantly increased, and the proliferation of germ cells was inhibited. In addition, THS lowered serum testosterone (T) level, whereas the levels of follicle stimulating hormone and luteinizing hormone were not significantly changed. The ultrastructure of the seminiferous tubules became abnormal after THS, the structure of the blood-testis barrier (BTB) became loose, and the Sertoli cells showed a trend of differentiation. The level of phosphorylated Akt was reduced, whereas the amount of phosphorylated NF-κB p65 was augmented by THS. Wuzi-Yanzong (WZYZ), a classic Chinese medicine prescription for the treatment of male reproductive dysfunctions, alleviated the changes induced by THS. In order to determine the mechanism of action of WZYZ, we investigated how this preparation modulated the levels of T, androgen receptor (AR), erythropoietin (EPO), EPO receptor, and Tyro-3, Axl, and Mer (TAM) family of tyrosine kinase receptors. We found that WZYZ activated the Akt pathway, inhibited the Toll-like receptor/MyD88/NF-κB pathway, and repaired the structure of BTB by regulating the levels of T, AR, TAM receptors, and EPO. In conclusion, these results suggest that WZYZ activates the Akt pathway and inhibits the NF-κB pathway by acting on the upstream regulators, thereby improving spermatogenesis deficit induced by THS.