高脂饮食诱导小鼠血糖增高损伤睾丸微血管功能

High fat diet-induced elevation of blood glucose impairs the microvascular function of testis in mice

目的观察高脂饮食诱导C57BL/6雄性小鼠血糖升高对睾丸微血管功能及雄性生殖的影响。方法将小鼠随机分为对照组(control)和高脂组(HFD),各20只。HFD组高脂饮食20周,每周测血糖及体质量;腹腔注射伊文思蓝观察血睾屏障通透性;激光多普勒检测睾丸微循环血流量及微血管自律运动频率和振幅;HE染色观察睾丸组织形态;免疫组化检测睾丸微血管血小板内皮细胞黏附分子-1(CD31)及生精细胞增殖细胞核抗原PCNA表达;TUNEL染色法观察生精细胞凋亡。结果 HFD组小鼠体质量及血糖均高于对照组(P<0.01);血睾屏障完整性破坏,生精小管通透性增高;睾丸平均血流灌注水平及微血管自律运动频率和振幅均低于对照组(P<0.01);生精上皮细胞数量减少、生精上皮变薄;微血管内皮细胞CD31及生精细胞PCNA表达水平均低于对照组(P<0.01);生精细胞凋亡水平高于对照组(P<0.01)。结论高脂饮食可诱导小鼠血糖水平增高致睾丸微血管损伤破坏血睾屏障完整性使小鼠生精上皮结构受损。

Objective To observe the effects of high fat diet-induced elevation of blood glucose on the microvascular function of testis and male reproduction in C57 BL/6 mice. Methods A total of 40 male C57 BL/6 mice were randomly divided into control group and high fat diet（ HFD） group（ n = 20）. The mice in HFD group were fed with high fat diet for 20 weeks. Blood glucose and body weight were measured weekly. The permeability of blood-testis barrier was evaluated by intraperitoneal injection of Evans blue. The blood flow of testicular microcirculation and the frequency and amplitude of microvascular vasomotion were detected by laser Doppler blood flow imaging system. The morphology of testicular tissue was observed by HE staining. The expressions of plateletendothelial cell adhesion molecule-1（ PECAM-1/CD31） in testicular microvascular endothelial cells and proliferating cell nuclear antigen（ PCNA） in spermatogenic cells were detected by immunohistochemistry. The apoptosis of spermatogenic cells was observed by TUNEL staining. Results The body weight and blood glucose of HFD groupwere significantly higher than those in control group（ P〈0. 01）. Evans blue staining showed that the integrity of blood-testis barrier of HFD group was damaged,and increased permeability was observed in seminiferous tubules.In HFD group,the mean blood flow of testis and the frequency and amplitude of microvascular vasomotion were significantly lower than those in control group（ P〈0. 01）. The number of spermatogenic epithelial cells and the thickness of seminiferous epithelium decreased. The expressions of CD31 in microvascular endothelial cells and PCNA in spermatogenic cells were significantly lower in HFD group than those in control group（ P〈0. 01）. The apoptosis level of spermatogenic cells was higher than that in the control group（ P〈0. 01）. Conclusions Increased blood glucose level induced by high fat diet in mice can impair the testicular microvasculature and damage the integrity of blood-testis barrier and injure the structure of seminiferous epithelium in mice.