Hypoglycemic effect of panaxnotoginseng polysaccharides in diabetic model rats and its therapeutic effect on diabetic retinopathy and their mechanisms / 吉林大学学报(医学版)

ABSTRACT

Objective:To establish rat diabetes and eye disease models by injection of STZ and explore the therapeutic effect of panaxnotoginseng polysaccharides (PNP) on the diabetes and eye diseases of the model rats,and to clarify their mechanisms.Methods:Seventy SD male rats were randomly divided into blank control (n=10) and model groups (n=60), and the rats in model group were fed with high fat diet. 2 weeks later, the rats in model group were intraperitoneally injected with 35 mg·kg-1 STZ to establish the models.And 3 d later, the rats were treated with fasting and water deprivation for 12 h,the fasting blood glucose (FBG)was tested, and the models were assessed to be successful as the FBG>11.1 mmol·L-1.The rats with hyperglycemia were selected and divided into model, melbine(150 mg·kg-1), and low, middle and high doses (75,150 and 300 mg·kg-1) of PNP groups.After orally administration for 5 and 8 weeks, the FBG levels of rats were recorded.And 8 weeks later, the sugar tolerance, hepatic glycogen levels,serum glutathione(GSH) and nitric oxide(NO) levels of the rats were tested.The rat retinas were removed to analyze the expression levels of vascular endothelial growth factor(VEGF) and inducible nitric oxide synthase(iNOS) by using Q-PCR.The pathological changes of retinas were observed by HE staining method.Results:Compared with model group,the FBG level in middle dose of PNP group was decreased 5 weeks after treatment(P<0.05).Eight weeks later, compared with model group, the levels of FBG, sugar tolerance and hepatic glycogen in different doses of PNP groups were all decreased (P<0.05 or P<0.01).Compared with model group, the level of serum GSH in high dose of PNP group was remarkably increased(P<0.01), and the NO level was significantly decreased (P<0.05 or P<0.01).Compared with model group, the expression levels of VEGF and iNOS in high dose of PNP group were significantly decreased (P<0.05).The results of HE staining showed that the neurodeatrophia of the rats in low and middle doses of PNP groups were improved;and the vascular proliferation and neurodeatrophia of the rats in high dose of PNP group were significantly improved.Conclusion:PNP could decrease the blood sugar, increase the levels of GSH and NO, and up-regulate the gene expression levels of VEGF and iNOS, resulting the treatment of diabetes and its related retinopathy.