An exploration on the protective mechanism of Xuduan Zhongzi prescription against epididymis oxidative damage in oligoasthenospermia model rats based on Nrf2-NQO1/γ-GCS signaling pathway

Objective: To investigate the protective mechanism of Xuduan Zhongzi prescription against epididymal oxidative damage in oligoasthenospermia model rats. Methods: Forty SD rats were randomly divided into blank group, model group, Xuduan Zhongzi prescription group (10g/kg)and L-carnitine group(0.1g/kg). Except blank group, all induced oligoasmospermia. The blank group and model group were given normal saline intragastric administration, the Xuduan Zhongzi prescription group was given Xuduan Zhongzi prescription solution intragastric administration, and the L-carnitine group was given L-carnitine intragastric administration. HE staining was used to observe the epididymis structure after 8 weeks. The concentration and activity rate of epididymis sperm were measured by sperm quality. MRNA and protein expression levels of Nrf2, NQO1 and γ -GCs in epididymis were detected by RT-qPCR and immunohistochemistry. Results: ①HE staining: in the blank group, the epididymis tubes were arranged tightly and regularly, the tissue structure was complete, the epithelial cells were arranged orderly, and the lumen sperm were numerous and evenly distributed. The epididymis of model group showed structural atrophy, loose arrangement, enlarged mesenchyme, increased cell debris and significantly reduced sperm cells. Compared with the model group, the lumen lesions of epididymis in Xuduan Zhongzi prescription group and L-carnitine group were significantly improved, and the amount of normal sperm in lumen was increased and the distribution was uniform. ② Results of sperm quality comparison among each group: sperm density and sperm motility rate: compared with blank group, sperm density and sperm motility rate in other groups were significantly decreased (P < 0.05), and sperm density and sperm motility rate in model group were significantly decreased (P < 0.05); Compared with model group, the sperm density and motility rate in Xuduan Zhongzi prescription group and L-carnitine group were significantly increased (P < 0.05). ③RT-qPCR and immunohistochemistry: Compared with the blank group, the mRNA and protein levels of Nrf2, NQO1 and γ -GCs in epididymal rats in model group were significantly decreased (P<0.05), while the mRNA and protein levels of Nrf2, NQO1 and γ -GCs were significantly increased in L-carnitine group and Continua seed formula group (P<0.05). Conclusion: Xuduan Zhongzi prescription can reduce oxidative stress damage and improve sperm quality of oligoasthenospermia. The mechanism may related to promoting the activation of Nrf2-NQO1/γ-GCS pathway in epididymis of oligoasthenospermia rats, and up-regulate the expressions of Nrf2, NQO1 and γ-GCS proteins.