石榴花多酚改善糖尿病大鼠肾损伤的机制研究

Mechanism of pomegranate flower polyphenol in ameliorating kidney injury in diabetic rats

目的探讨石榴花多酚对糖尿病肾损伤的作用及其可能的机制。方法40只SD大鼠随机分为对照组、模型组、石榴花多酚组和地昔帕明组各10只,高脂饲料饲喂联合链脲佐菌素(streptozocin,STZ)诱导建立糖尿病大鼠模型。检测大鼠血糖、尿素氮(BUN)、血肌酐(S-Cr)和24 h尿蛋白含量,PAS染色和Masson染色观察大鼠肾脏病理学变化,TUNEL染色检测大鼠肾细胞凋亡率,免疫组化和RT-PCR检测大鼠GRP78和CHOP表达水平,Western blot检测酸性鞘磷脂酶(acid sphingomyelinase,ASMase)蛋白表达水平。结果与模型组比较,石榴花多酚组和地昔帕明组大鼠血糖水平、BUN、S-Cr、24 h尿蛋白含量和肾细胞凋亡率显著降低,肾小球体积、GRP78、CHOP和ASMase表达显著降低,差异均有统计学意义(P<0.05)。显微镜下观察,与模型组比较,石榴花多酚组和地昔帕明组大鼠的肾组织病理学损伤明显改善,胶原纤维沉积减少。结论石榴花多酚通过抑制酸性神经鞘磷脂酶和内质网应激改善大鼠糖尿病肾损伤。

Objective To explore the effects of pomegranate flower polyphenol on diabetic nephropathy and its possible mechanism.Methods 40 SD rats were randomly divided into control group,model group,pomegranate flower polyphenol group and desipramine group,with 10 rats in each group.A rat model of diabetes was established by feeding high-fat diet combined with streptozotocin(STZ).Levels of blood glucose,urea nitrogen(BUN),blood creatinine(S-Cr)and 24 h urine protein content of rats were tested.PAS staining and Masson staining were used to observe the pathological changes of rat kidneys.TUNEL staining was used to detect the apoptosis rate of rat kidney cells.Immunohistochemistry and RT-PCR were used to detect the expression levels of GRP78 and CHOP in rats.Western blot was used to detect the expression level of acid sphingomyelinase(ASMase)protein.Results Compared with the model group,the levels of blood glucose,BUN,S-Cr,24 h urine protein content and apoptosis rate of kidney cells of the pomegranate flower polyphenol group and the desipramine group were significantly decreased,glomerular volume and the expressions of GRP78,CHOP and ASMase were significantly decreased,and the differences were statistically significant(P<0.05).Under the microscope,compared with the model group,the renal histopathological damage of the pomegranate flower polyphenol group and the desipramine group was significantly ameliorated,and the deposition of collagen fibers was reduced.Conclusions Pomegranate flower polyphenol can ameliorate diabetic nephropathy in rats by inhibiting acid sphingomyelinase and endoplasmic reticulum stress.