[Improving effect and mechanism of Bugan Decoction on sperm quality in mice with exercise-induced fatigue via PARP-1]

This study aimed to investigate the effect and mechanism of Bugan Decoction on spermatogenesis in mice with exercise-induced fatigue. Male ICR mice were screened by swimming training and randomly divided into seven groups(n=10 per group): a blank group, a model group, low-, medium-, and high-dose Bugan Decoction groups, an olaparib group, and a vitamin C group. Except for the blank group, the other groups were subjected to weight-loaded swimming training to establish the exercise-induced fatigue model. After weight-loaded swimming, the low-, medium-, and high-dose Bugan Decoction groups were intragastrically administered 0.149, 0.298, and 0.596 g·kg~(-1) Bugan Decoction, respectively; the olaparib group received intraperitoneal injection of 0.05 g·kg~(-1) olaparib; the vitamin C group was intragastrically given 0.2 g·kg~(-1) vitamin C; the blank group and model group were gavaged with an equal volume of normal saline. The administration lasted for 2 consecutive weeks. At the end of the experiment, the final exhaustive swimming time of mice in each group was recorded. Commercial kits were used to detect the levels of urea nitrogen(BUN), lactic acid(LA), lactate dehydrogenase(LDH), superoxide dismutase(SOD), malondialdehyde(MDA), glutathione peroxidase(GSH-Px) in serum, and testicular testosterone(T), interleukin-6(IL-6), interleukin-1β(IL-1β), tumor necrosis factor-α(TNF-α) in testes. Pathological morphological changes of muscle and testicular tissues, as well as epididymal sperm quality, were observed. Sperm mitochondrial membrane potential was detected by flow cytometry. Testicular mitochondrial morphology was observed by electron microscopy. Western blot was used to determine the protein expression of poly(ADP-ribose) polymerase-1(PARP-1), p38 mitogen-activated protein kinase(p38 MAPK), phospho-p38 MAPK(p-p38), c-Jun N-terminal kinase(JNK), phospho-JNK(p-JNK), cleaved caspase-3, B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), and IL-6 in testes. Immunofluorescence was performed to detect PARP-1 expression in testes. Animal experimental results showed that compared with the blank group, the model group exhibited significant fatigue-related phenotypes, accompanied by increased levels of serum fatigue metabolites, decreased activities of antioxidant enzymes, upregulated expression of local inflammatory factors in testicular tissues, decreased T level, abnormal activation of apoptosis and stress-related pathway proteins, reduced sperm quality, damaged mitochondrial membrane potential, and abnormal morphological structure of testicular mitochondria. Compared with the model group, the medium-and high-dose Bugan Decoction groups and olaparib group significantly improved the above indicators: increased body weight and exhaustive swimming time, decreased serum levels of LA, LDH, BUN, and MDA, increased activities of SOD and GSH-Px, downregulated expression of inflammatory factors in testicular tissue, recovered T level, inhibited activation of apoptosis and stress-related pathway proteins, improved sperm quality, alleviated mitochondrial membrane potential damage, and restored the morphological structure of testicular mitochondria. In conclusion, Bugan Decoction can improve testicular mitochondrial dysfunction by inhibiting the PARP-1/p38 MAPK/JNK pathway, reduce testicular cell apoptosis and local inflammatory response, maintain stable T levels and a normal spermatogenic microenvironment, and ultimately improve sperm quality.