三聚氰胺对雄性小鼠睾丸生精细胞凋亡的影响

Effect of Melamine on Apoptosis of Spermatogenic Cells in Testis of Male Mice

目的:探讨三聚氰胺对雄性小鼠睾丸生精细胞凋亡的影响。方法:健康雄性昆明种小鼠50只随机均分为阴性对照组、实验组(三聚氰胺低、中、高剂量组)及阳性对照组,阴性对照组按0.1mL/10g体质量灌胃生理盐水,三聚氰胺低、中、高剂量组分别按400、800、1600mg/kg,阳性对照组腹腔注射环磷酰胺40mg/kg,各剂量组按照体质量每天定时经口给药1次,连续5d,于首次给药后的第35天处死各组小鼠;睾丸病理切片HE染色,观察小鼠睾丸组织的病理学改变,流式细胞术检测小鼠睾丸生精细胞凋亡率,免疫组化法检查凋亡相关蛋白Bcl-2、Bax、Caspase-3的阳性表达情况。结果:三聚氰胺各剂量组睾丸形态结构随着染毒剂量的增加出现不同程度的损伤,睾丸细胞凋亡率呈上升趋势,其中高剂量组与阴性对照组比较,差异有统计学意义(P<0.05);三聚氰胺低、中、高剂量组Bcl-2表达均呈下降趋势,与阴性对照组比较,差异均有统计学意义(P<0.05);Bax各组表达呈上升趋势,三聚氰胺中剂量组、高剂量组Bax的表达与阴性对照组比较,差异有统计学意义(P<0.05);Caspase-3表达亦呈上升趋势,三聚氰胺中、高剂量组Caspase-3的表达与阴性对照组比较,差异有统计学意义(P<0.05)。结论:三聚氰胺促进雄性小鼠睾丸生精细胞凋亡,其机制可能与下调抗凋亡蛋白Bcl-2的表达和上调促凋亡蛋白Bax、Caspase-3的表达有关。

Objective:To investigate the effect of melamine on apoptosis of spermatogenic cells in testis of male mice.Methods:Fifty male Kunming mice were randomly divided into 5 groups:saline negative control group(0.01 mL/10 g intragastric treatment),the experimental group of melamine low dosage,medium dosage and high dosage group(400,800,1 600 mg/kg treatment),and the positive control group(40 mg/kg CP ip treatment)with equal number.Mice in each experiment group were administered orally for consecutive 5 days in accordance with body mass.35 days after the first administration,mice were sacrificed.To observe pathologic changes of testis in mice by HE section staining;to detect the apoptosis conditions of spermatogenic cells by the flow cytometry;to detect Bcl-2,Bax and Caspase-3 positive expression with immunohistochemical techniques.Results:The testicular morphology of each dosage group showed different degrees of damage.Apoptosis percentage in all groups increased.The apoptosis percentage in high dosage group was different compared with the negative control group(P<0.05);the expression of Bcl-2 in all dose groups were significantly reduced,the difference was statistically significant compared with negative control group(P<0.05).The expression of Bax and Caspase-3 increased significantly in the medium dose group and the high dose group compared with the negative control group,differences were statistically significant(P<0.05).Conclusions:Melamine significantly induced apoptosis of spermatogenic cells in testis of male mice,the mechanism may be related to the down-regulation of anti-apoptotic protein Bcl-2 and up-regulation of apoptotic protein Bax and Caspase-3.