[Xiongcan Yishen Formula up-regulates the clock gene expressions in the testis tissue of the rats with late-onset hypogonadism].

Objective: To investigate the effect of Xiongcan Yishen Formula (XYF) on the expressions of the clock genes in the testis tissue of the rats with late-onset hypogonadism (LOH).

Methods: Forty-eight 8-week-old male SD rats were randomly divided into 6 groups, normal control, model control, testosterone propionate (TP), and low-, medium- and high-dose XYF. The LOH model was made in the later 5 groups of rats by intraperitoneal injection of D-galactose at 480 mg/kg/d for 56 successive days, while the normal controls were injected with the same volume of normal saline. After modeling, the rats in the low-, medium- and high-dose XYF groups were treated intragastrically with XYF at 10.4, 20.8 and 41.6 g/kg/d, bid, respectively, those in the normal and model control groups with the same volume of distilled water, and those in the TP group intramuscularly with TP at 5.21 mg/kg/d, qd alt, all for 28 days. After treatment, the supernatant was obtained for measurement of the serum T level by ELISA, and the testis tissue collected for determination of the mRNA and protein expressions of BMAL1, NR1D1, PER2, CRY1, StAR and CYP11A1 by RT-qPCR and Western blot.

Results: Compared with the normal controls, the rats in the LOH model control group showed significantly decreased serum T and mRNA and protein expressions of BMAL1, NR1D1, PER2, CRY1, StAR and CYP11A1 (P < 0.05). In comparison with the findings in the model controls, the T level was remarkably increased in the TP and XYF groups (P < 0.05), the expressions of StAR mRNA and CYP11A1 mRNA and protein markedly up-regulated in the high-dose XYF group (P < 0.05), and so was the expression of the StAR protein in the XYF and TP groups (P < 0.05), those of BMAL1 and NR1D1 proteins and PER2 mRNA and protein in the high-dose XYF group (P < 0.05), those of BMAL1 mRNA and CRY1 protein in the medium- and high-dose XYF groups (P < 0.05), that of NR1D1 mRNA in the XYF and TP groups (P < 0.05), and that of CRY1 mRNA in the medium- and high-dose XYF and TP groups (P < 0.05).

Conclusion: Xiongcan Yishen Formula could up-regulate the expressions of the clock genes in the testis tissue of the LOH rats and increase the serum T level as well, which may underlie the mechanisms of Xiongcan Yishen Formula acting on LOH.