[Expression of G-protein coupled estrogen receptor in the testis of the male mouse with kidney yin or kidney yang deficiency and its impact on the reproductive function of the mouse].

Objective: To investigate the expression of the G-protein coupled estrogen receptor (GPER) in the testis of the male mouse with kidney yin or kidney yang deficiency and its influence on the reproductive function of the mouse.

Methods: We randomized 30 six-week-old male Kunming mice into three groups of equal number: kidney yang deficiency, kidney yin deficiency, and normal control, and established the models of kidney yang deficiency and kidney yin deficiency by peritoneal injection of hydrocortisone at 50 mg/kg for 5 days and 25 mg/kg for 10 days, respectively. We observed the behavioral changes of the mice using the elevated plus-maze, exhaustive swimming and field experiment, examined the semen quality with the automatic sperm quality analyzer, calculated the average number of the offspring, measured the serum testosterone (T) and estradiol (E2) levels and T/E2 ratio by Roche electrochemiluminescence assay, and determined the localization and expression of GPER in the testis by immunohistochemistry and immunofluorescence staining.

Results: Compared with the mice with kidney yin deficiency, those with kidney yang deficiency showed remarkably fewer entries into the open arm and central area (P <0.05) and shorter time of exhaustive swimming (P <0.05), but no statistically significant difference in the time spent in the open arm or the central area (P >0.05); the latter group also exhibited significant decreases in the epididymal sperm count (［7.27 ± 1.30］ vs ［3.05 ± 1.06］ ×108/g, P <0.01), sperm motility (［54.15 ± 13.52］ vs ［51.57 ± 8.75］ %, P <0.01) and average number of the offspring (6.46 vs 4.33, P <0.05), a slight increase in the rate of morphologically abnormal sperm (［13.42 ± 2.32］ vs ［15.39 ± 2.48］ %, P >0.05), and markedly reduced serum T (［24.96 ± 6.18］ vs ［16.72 ± 5.92］ ng/dl,P <0.05), E2 (［19.81 ± 4.01］ vs ［15.24 ± 1.11］ pg/ml,P <0.05) and T/E2 ratio (1.41 vs 1.25, P <0.05). The expression of GPER was found in the cytoplasm of the Leydig cells, negative in the nuclei and cell membrane, significantly higher in the kidney yang than in the kidney yin deficiency group (P <0.05).

Conclusions: The numbers of sperm and offspring decreased while the percentage of morphologically abnormal sperm increased in both the kidney yang and kidney yin deficiency mice, even more significantly in the former, which might be associated with the up-regulated expression of GPER in the testis of the mouse with kidney yang deficiency and consequently the reduced serum T level and T/E2 ratio.