生长激素释放肽对糖尿病大鼠视网膜病变的保护作用

Protective effect and mechanism of growth hormone releasing peptide on diabetic retinopathy in rats

目的:探讨生长激素释放肽(ghrelin)对糖尿病大鼠视网膜病变的影响并研究其保护作用。方法:雄性SD大鼠18只分为对照组、模型组、ghrelin组,采用HE染色观察视网膜形态,TUNEL染色观察细胞凋亡,透射电镜观察视网膜色素上皮层超微结构,免疫组化检测氧化应激指标,ELISA检测炎性因子含量。结果:形态学观察结果显示,ghrelin可减轻视网膜组织损伤程度,降低糖尿病大鼠视网膜组织细胞凋亡;免疫组化结果显示,与模型组比较,ghrelin组大鼠视网膜组织中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-PX)活性升高,丙二醛(MDA)含量下降(P<0.05);ELISA结果显示,模型组细胞间黏附分子-1(ICAM-1)、肿瘤坏死因子-a(TNF-a)及白细胞介素-1β(IL-1β)表达较对照组升高(P<0.05),ghrelin干预后,炎症因子表达均下降,与模型组比较有差异(P<0.05)。结论:Ghrelin治疗糖尿病大鼠后,能有效延缓糖尿病大鼠视网膜病变的进程,其作用机制与降低氧化应激水平、抑制炎症反应相关。

AIM:To investigate the effect of growth hormone releasing peptide(ghrelin)on diabetic retinopathy in rats and study its protective effect.METHODS:Eighteen male SD rats were divided into control group,model group and ghrelin group.HE staining was used to observe the morphology of retina,TUNEL staining was used to observe apoptosis,transmission electron microscope was used to observe the ultrastructure of retinal pigment epithelium,immunohistochemistry was used to detect oxidative stress index,and ELISA was used to detect the content of inflammatory factors.RESULTS:Morphological observation showed that ghrelin could reduce the degree of retinal tissue damage and the apoptosis of retinal tissue in diabetic rats.The results of immunohistochemistry showed that the activities of SOD(superoxide dismutase)and glutathione peroxidase(GSH-Px)in retina tissue of ghrelin group were increased,and the content of malondialdehyde(MDA)was decreased,compared with model group(P<0.05).ELISA results showed that intercellular cell adhesion molecule-1(ICAM-1),tumor necrosis factor-a,(TNF-a)and interleukin-1β(IL-1β)in model group were significantly higher than those in control group(P<0.05).After ghrelin intervention,the expression of inflammatory factors decreased,compared with model group(P<0.05).CONCLUSION:Ghrelin could effectively retard the progression of diabetic retinopathy in diabetic rats,and its mechanism was related to lowering the level of oxidative stress and inhibiting inflammation.