High fat diet-induced elevation of blood glucose impairs the microvascular function of testis in mice / 基础医学与临床

ABSTRACT

Objective To observe the effects of high fat dietinduced elevation of blood glucose on the microvascular function of testis and male reproduction in C57BL/6 mice. Methods A total of 40 male C57BL/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 bloodtestis barrier was evaluated by intraperitoneal injection of Evans blue. The blood flow of testicular microcircu-lation and the frequency and amplitude of microvascular vasomotion were detected by laser Doppler blood flow ima-ging system. The morphology of testicular tissue was observed by HE staining. The expressions of platelet- endothelial cell adhesion molecule-1 (PECAM-1/CD31) in testicular microvascular endothelial cells and prolifera-ting 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 group were 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 sig-nificantly 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.