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.%目的:通过注射链脲佐菌素(STZ)制备大鼠糖尿病眼病模型,探讨三七多糖对糖尿病模型大鼠的降血糖作用及其眼病的治疗作用,阐明其作用机制.方法:70只SD雄性大鼠分为对照组(10只)和造模组(60只),造模组大鼠给予高脂饲料喂养.2周后,造模组大鼠腹腔注射35 mg·kg-1STZ制备高血糖模型.3 d后,动物禁食不禁水12 h,检测空腹血糖(FBG)水平,以FBG>11.1 mmol·L-1为造模成功标准.选取造模成功的大鼠,随机分为模型组,二甲双胍(150 mg·kg-1)组,低、中、高剂量(75、150和300 mg·kg-1)三七多糖组.灌胃给药5和8周后检测大鼠FBG水平,8周后检测大鼠糖耐量,处死大鼠取肝脏检测肝糖原水平,检测血清谷胱甘肽(GSH)和一氧化氮(NO)水平.分离大鼠视网膜,Q-PCR法检测血管内皮生长因子(VEGF)及诱导型一氧化氮合酶(iNOS)的表达水平,HE染色观察其组织形态表现.结果:与模型组比较,用药5周后,中剂量三七多糖组大鼠FBG水平明显降低(P<0.05);用药8周后,不同剂量三七多糖组大鼠FBG、糖耐量和肝糖原水平明显降低(P<0.05或P<0.01).血清检测,与模型组比较,高剂量三七多糖组大鼠GSH水平明显升高,NO水平明显降低(P<0.05或P<0.01).Q-PCR法检测,与模型组比较,高剂量三七多糖组大鼠视网膜中VEGF和iNOS表达水平明显降低(P<0.05).HE染色,与模型组比较,中和低剂量三七多糖组大鼠视网膜部分血管增生,未见视网膜萎缩;高剂量三七多糖组大鼠视网膜血管增生状态明显改善,未见视网膜萎缩.结论:三七多糖具有降血糖的作用,同时可以通过升高GSH和NO水平、提高VEGF和iNOS基因表达水平,起到治疗糖尿病引起的视网膜病变的作用.
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