实验性Ⅱ型糖尿病大鼠模型复制方法的改进及其评价

Development and Evaluation of a Modeling Method For Experimental Rat with Type 2 Diabetes Mellitus

目的建立一种快速简便的Ⅱ型糖尿病（T2DM）大鼠模型并观察其胰岛及’肾脏的病理学变化。方法雄性SD大鼠随机分为3组：（1）对照组，尾静脉注射0．1mol／L柠檬酸缓冲液，普通饲料喂养；（2）鸡蛋饲料组，尾静脉注射0．1mmol／L柠檬酸缓冲液，50％鸡蛋饲料喂养；（3）模型组，尾静脉一次性注射30mg／kg链脲佐菌素（STZ），50％鸡蛋饲料喂养。4周后所有大鼠进行口服糖耐量实验（OGTT）。测定24h尿微量白蛋白（U-ALB）和尿肌酐（U-CREA）水平。采血测定空腹血糖（FBG）、胰岛素（Fins）、血脂（TG和TC、FFA）、SOD、MDA水平。免疫组化染色观察胰岛B细胞的形态学改变。左肾称重并计算肾脏指数（KI），右肾进行病理学观察。结果与对照组比较，模型组大鼠的体重增加（P〈0．05），FBG、Fins、TG、TC、FFA、MDA水平升高（P〈0．05），SOD水平、ISI显著降低（P〈0．05）。胰岛体积明显变小，散在分布。24h尿液、U—ALB、U—CREA和KI均增加（P〈0．05），光镜和电镜结果表明肾小球毛细血管基底膜不均匀增厚，足突大部分增宽融合，说明该模型还伴有早期的肾脏损害。结论该方法成功地制备了T2DM大鼠模型，STZ用量少，饲料配制方便，时间短，成模率高，死亡率低，可用于T2DM及其慢性并发症糖尿病肾病（DN）的发病机制及治疗的研究。

Objective To establish a fast and convinient type 2 diabetes mellitus （T2DM） rat model. Methods Six-week-old male SD rats were randomly allocated into three groups： normal control group, egg-diet group and model group. The model rats were injected intraperitoneally with 30 mg/kg streptozotocin （STZ）, then fed egg-diet for 4 weeks to induce diabetes. NC group rats were fed normal chow diet for 4 weeks. Egg-diet group rats were fed egg-diet for 4 weeks. Islet function in each group was evaluated by oral glucose tolerance test （OGTT）. 24hr urine specimen was collected and used to analyze urinary albumin and creatinine content. The serum biochemical indices such as FBG, Fins, TG, TC, FFA, SOD, MDA levels were measured. Islets were examined with immunohistochemical analysis of insulin. Kidneys were evalutated with HE staining and transmission electron microscopy respectively. Results Compared with NC rats, the body weight in model group and egg-diet group was increased markedly. Levels of FBG, Fins, TG, TC, MDA in model groups were increased significantly, while SOD levels and ISI values were decreased significantly. 24hr urine excretion, urine albumin and creatinine level in model group were all increased markedly. The pancreatic islets appeared smaller significantly in model group than in NC group. The kidneys in model rats became hypertrophic and kidney indices were increased significantly than in NC rats. Pathological examination showed that basilar membrane in model rats became asymmetrical thicken, foot protrusions became widen and fused mutually. Conclusions This method for improving T2DM rat model was high-efficient, stable and had low death rate, suitable for studying the mechanism and therapy of type 2 diabete mellitus and its chronic complications especially diabetic nephropathy.