摘要Background:Aspermia caused by exogenous testosterone limit its usage in late-onset hypogonadism (LOH) patients desiring fertility.Saikokaryukotsuboreito (SKRBT) is reported to improve serum testosterone and relieve LOH-related symptoms.However,it is unclear whether SKRBT affects fertility.We aimed to examine the effects of SKRBT on spermatogenesis and fertility in aging male mice.Methods:Thirty aging male mice were randomly assigned to three groups.Mice were orally administered with phosphate-buffer solution or SKRBT (300 mg/kg,daily) or received testosterone by subcutaneous injections (10 mg/kg,every 3 days).Thirty days later,each male mouse was mated with two female mice.All animals were sacrificed at the end of 90 days.Intratesticular testosterone (ITT) levels,quality of sperm,expression of synaptonemal complex protein 3 (SYCP3),and fertility were assayed.Results:In the SKRBT-treated group,ITT,quality of sperm,and expression of SYCP3 were all improved compared with the control group (ITT:85.50± 12.31 ng/gvs.74.10± 11.45 ng/g,P=0.027;sperm number:[14.94± 4.63] × 106 cells/ml vs.[8.79±4.38] × 106 cells/ml,P =0.002;sperm motility:43.16 ± 9.93％ vs.33.51 ± 6.98％,P =0.015;the number of SYCP3-positive cells/tubule:77.50 ± 11.01 ng/ml vs.49.30 ± 8.73 ng/ml,P ＜ 0.001;the expression of SYCP3 protein:1.23 ± 0.09 vs.0.84 ± 0.10,P ＜ 0.001),but fertility was not significantly changed (P ＞ 0.05,respectively).In the testosterone-treated group,ITT,quality of sperm,and expression of SYCP3 were markedly lower than the control group (ITT:59.00 ± 8.67,P =0.005;sperm number:[4.34 ± 2.45] × l06 cells/ml,P =0.018;sperm motility:19.53 ± 7.69％,P =0.001;the number of SYCP3-positive cells/tubule:30.00 ± 11.28,P ＜ 0.001;the percentage of SYCP3-positive tubules/section 71.98 ± 8.88％,P =0.001;the expression of SYCP3 protein:0.71 ± 0.09,P ＜ 0.001),and fertility was also suppressed (P ＜ 0.05,respectively).Conclusion:SKRBT had no adverse effect on fertility potential in aging male mice.