Baicalin Protects Mouse Testis From Injury Induced by PM_2.5 Associated With the DKK1-Wnt/β-Catenin Signaling Pathway

Fine particulate matter (PM_2.5) has a damaging effect on the male reproductive system. Baicalin has excellent anti-inflammatory and antioxidant pharmacological functions. The main purpose of this study was to investigate whether baicalin had a protective effect against PM_2.5-induced damage to the reproductive system of mice, and to further investigate the mechanism of the protective effect of baicalin. In our experiment, baicalin was administered by gavage 1 h before PM_2.5 exposure, followed by exposure to PM_2.5 with an oral-nasal exposure system at 750 μg/m³ for 4 h/day, and this experiment was continued for 45 days until the model was established. The results indicated that PM_2.5 exposure decreased testicular weight and organ coefficient, sperm count, and serum testosterone level, and down-regulated the mRNA and protein expressions of StAR, CYP11A1, and CYP17A1, which related to testosterone synthesis. After baicalin treatment, our experimental results showed that the 50 and 100 mg/kg baicalin groups showed a gradual increase in sperm counts, testosterone levels, and a significant restoration of genes and protein related to testosterone synthesis and the DKK1-Wnt/β-catenin signaling pathway. In conclusion, baicalin might play a protective role in promoting testicular tissue repair, and this may be associated with the regulation of the DKK1 - Wnt/β-catenin signaling pathway.