摘要
目的探讨丝胶对糖尿病大鼠视网膜氧化应激和微炎症状态的改善作用。方法采用高脂高糖饲料喂养联合链脲佐菌素腹腔注射法建立糖尿病大鼠模型,将24只成模大鼠随机分为丝胶治疗组和糖尿病模型组,每组12只,另取同周龄12只正常大鼠作为正常对照组,成模后丝胶治疗组给予丝胶溶液空腹灌胃、糖尿病模型组及正常对照组给予等体积生理盐水灌胃每天1次,共35 d。药物干预后,检测3组视网膜组织中丙二醛(malondialdehyde,MDA)、还原型谷胱甘肽(glutathione,GSH)的含量;采用Western blot法检测视网膜核因子E2相关因子2(nuclear factor erythroid 2-related factor 2,Nrf2)、血红素氧合酶1(heme oxygenase 1,HO-1)、核因子-κB(nuclear factor kappa-B,NF-κB)和肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)蛋白的表达,苏木素-伊红染色法观察视网膜形态结构。结果各指标三组间整体比较差异显著(均为P<0.01)。丝胶治疗组大鼠视网膜中MDA含量、NF-κB和TNF-α蛋白表达水平分别为(4.145±0.282)mmol·gprot-1、0.232±0.027和0.761±0.058,较糖尿病模型组的(6.813±0.446)mmol·gprot-1、0.334±0.024、0.994±0.084均显著降低(均为P<0.05)。丝胶治疗组大鼠视网膜中还原型GSH含量、Nrf2和HO-1蛋白表达水平分别为(78.518±4.317)mg·gprot-1、0.591±0.054和0.954±0.091,较糖尿病模型组的(59.890±5.932)mg·gprot-1、0.351±0.044、0.585±0.054均显著升高(均为P<0.05)。糖尿病模型组大鼠视网膜各层细胞排列紊乱,内界膜肿胀,神经节细胞可见空泡、水肿样改变,丝胶治疗组大鼠视网膜各层细胞形态较规则、排列轻度紊乱,病理变化较糖尿病模型组明显减轻。结论丝胶可改善糖尿病视网膜氧化应激和炎症介质的损伤,延缓糖尿病视网膜病变发展。
Objective To investigate the improvement effects of sericin on the retinal oxidative stress and micro-inflammatory state in diabetic rats. Methods A diabetic rat model was established by using high-fat and high-sugar diet and intraperitoneal injection of streptozotocin.Then 24 diabetic rats were randomly divided into sericin treatment group and diabetic model group,with 12 rats for each group,and additional 12 normal rats with the same age were collected as a normal control group. Next,the rats in the sericin treatment group received sericin solution,while the other two groups was given the same amount of normal saline once a day for 35 days.After the agent intervention,the content of malondialdehyde( MDA) and glutathione( GSH) in the retina of all rats were detected by related kits. The expressions of nuclear factor erythroid 2-related factor 2( Nrf2),heme oxygenase 1( HO-1),nuclear factor-κB( NF-κB) and tumor necrosis factor-α( TNF-α) protein were detected by Western blot,and finally,the retinal morphology was examined by hematoxylin-eosin staining in the 3 groups. Results The content of MDA,NF-κB and TNF-α protein expression in the sericin treatment group was( 4. 145 ± 0. 282) mmol·gprot-1,0. 232 ± 0. 027 and 0. 761 ± 0. 058,respectively,which was significantly lower than that in the diabetic model group[( 6. 813 ± 0. 446) mmol·gprot-1,0. 334 ± 0. 024 and 0. 994 ± 0.084]( all P < 0. 05). The content of GSH,Nrf2 and HO-1 protein expression in rat retina in the sericin treatment group was( 78. 518 ± 4. 317) mg·gprot-1,0. 591 ± 0. 054 and 0. 954 ± 0. 091,respectively,which was significantly higher than that in the diabetic model group [( 59. 890 ± 5.932) mg · gprot-1,0. 351 ± 0. 044 and 0. 585 ± 0. 054]( all P < 0. 05). The diabetic model group presented the disorder arrangement of the neurocyte in different levels in the retina,irregular and swollen inner limiting membrane,vacuoles in the ganglion cells,but in the sericin treatment group,the morphology of retinal layers was more regular and mildly disorderly arranged. The pathological damages in the retina were alleviated significantly. Conclusion Sericin can ameliorate oxidative stress and inflammation in diabetic retina,thereby delaying the development of diabetic retinopathy.
引文
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