短暂轻度阴囊热应激对小鼠睾丸的损害作用

目的 探讨单次、短暂、轻度阴囊热处理（43℃，15 min）对小鼠睾丸的损害作用。方法 24只成年ICR雄性小鼠，随机分为4组。将热处理组小鼠身体的下1/3部分浸于43℃恒温水浴中15 min，于热处理后0.5 h、2 h和6 h取睾丸组织。将对照组小鼠下腹部浸入22℃水浴15 min，6 h后处死取睾丸组织。采用HE染色对睾丸组织进行病理学检查，采用TUNEL方法检测细胞凋亡，采用western blotting检测睾丸caspase-3蛋白表达。结果 热处理后6 h小鼠睾丸组织生精小管间隙增大，生精小管内细胞排列紊乱，胞浆空泡化明显，核固缩细胞增多，多核精细胞显著增加。与阴性对照组相比，阴囊热处理能够显著诱导小鼠睾丸生殖细胞凋亡，增加睾丸组织裂解型caspase-3蛋白的表达。结论 单次、短暂、轻度阴囊热处理（43℃，15 min）能够明显引起睾丸病理组织学损伤，诱导睾丸生殖细胞凋亡。

Damage effect of a single,mild, transient scrotal heat stress on mouse tests

Objective To evaluate the stress response in mouse testes following a single mild transient scrotal heat exposure (43 degrees C for 15 min).Methods Twenty-four male mice were randomly divided into four groups with six mice per group.Mice in scrotal hyperthermia group were subjected to a single heat stress of 43℃ (treated) for 15 min and killed at 0.5 h,2 h,and 6 h after heat exposure.The control mice were immersed in a water bath maintained at 22 ℃ and killed at 6 h after heat exposure.Histopathological analyses of testes were performed by hematoxylin and eosin (H&E) staining.Testicular germ cell apoptosis was determined by terminal dUTP nick-end labelling (TUNEL).The expression of testicular caspase-3 protein was measured using western blot.Results As expected,scrotal hyperthermia markedly increased the inside diameter of seminiferous tubules and disturbed the array of spermatogenic cells.Meanwhile,Scrotal hyperthermia clearly induced cytoplasmic vacuolization,pyknosis of nuclei and multinucleate spermatogenic cells in seminiferous tubules in heat-treated mice,especially at 6 h after heating.Paralleled with testicular lesion,acute scrotal hyperthermia significantly increased testicular germ cell apoptosis comparing with control group.In addition,scrotal hyperthermia obviously upregulated the expression level of active caspase-3 in testes.Conclusions A single,acute scrotal hyperthermia significantly induce testicular histological impairment and germ cell apoptosis.