链脲佐菌素构建糖尿病小鼠视网膜病变模型及评价

Streptozotocin-induced diabetic retinopathy in mice: model establishment and evaluation

目的建立链脲佐菌素(STZ)诱导的糖尿病小鼠视网膜病变模型,研究早期糖尿病小鼠视网膜的病理改变及其发展过程中血管内皮生长因子(VEGF)及其受体(VEGFR1、VEGFR2)在动物模型中的表达情况。方法 6~8周龄C57BL/6J小鼠腹腔连续注射STZ(55 mg/kg)5 d,注射后1周时测量空腹血糖浓度,将糖尿病模型建立成功的小鼠与对照组小鼠均喂养5个月。注射后5个月时,通过石蜡切片H-E染色、伊文思蓝灌注造影、视网膜血管网铺片等方法分析糖尿病小鼠视网膜组织形态变化。通过实时定量PCR、蛋白质印迹法分析糖尿病视网膜病变过程中VEGF及其受体VEGFR1、VEGFR2的表达情况。结果与对照组相比,注射后1周、1~5个月时模型组小鼠血糖水平均升高(均高于16.5 mmol/L),差异均有统计学意义(P均<0.01)。注射后5个月时模型组小鼠视网膜全层变薄,感光细胞层、内核层及外核层细胞数量减少,排列紊乱;血管走行迂曲,出现渗漏及渗漏斑;血管内皮细胞数量增加,形态改变,周细胞数量减少,可见无细胞毛细血管、管腔闭塞;VEGF、VEGFR1、VEGFR2的蛋白质和mRNA表达均增加,与对照组相比差异均有统计学意义(P均<0.01)。结论成功构建糖尿病小鼠视网膜病变模型,该模型表明在糖尿病发展5个月后出现增殖性糖尿病视网膜病变,且糖尿病小鼠视网膜中VEGF、VEGFR1和VEGFR2表达水平均上升。

Objective To establish streptozotocin(STZ)-induced diabetic retinopathy model in mice, and to observe the pathological changes of the retina in early diabetic stages and the expression of vascular endothelial growth factor(VEGF), vascular endothelial growth factor receptor(VEGFR)1 and VEGFR2 in the mouse model. Methods C57BL/6J mice, aged 6-8 weeks, received intraperitoneal injection of STZ(55 mg/kg) once a day for 5 d. The fasting blood glucose concentration was measured 1 week after injection. The diabetic and control mice were fed for 5 months. Then the morphological changes of retina in diabetic mice were analyzed by H-E staining, Evans blue perfusion angiography and retinal vascular network digestion. The expression of VEGF and its receptors VEGFR1, VEGFR2 in diabetic retinopathy was analyzed by quantitative real-time PCR and Western blotting. Results Compared with the control group, the blood glucose levels of the model group were significanlty increased 1 week, 1 to 5 months after injection(all higher than 16.5 mmol/L, all P<0.01). At 5 months after injection, the whole retina of the model group became thinner;the number of photoreceptor cells, inner and outer nuclear cells were decreased and disorderly arranged;the blood vessels went tortuously with leakage and leakage spots;the number of vascular endothelial cells was increased, with altered morphology;the number of peripheral cells was decreased;and there were no cellular capillaries and lumen occlusion. The expression levels of VEGF, VEGFR1 and VEGFR2 protein and mRNA were significantly increased in the model group compared with the control group(all P<0.01). Conclusion Diabetic retinopathy mouse model has been successfully constructed, with proliferative diabetic retinopathy appearing 5 months after diabetes, and the expression levels of VEGF, VEGFR1 and VEGFR2 are increased in the retina of diabetic mice.