应用自发性高血压大鼠建立2型糖尿病早期肾损害模型

Establishment of type 2 diabetes mellitus with early renal injury on spontaneously hypertensive rats

目的应用自发性高血压大鼠（SHR）建立具有胰岛素抵抗和早期肾脏损害特征的2型糖尿病模型。方法采用高糖高脂饲料喂养SHR大鼠2周诱导胰岛素抵抗，同时用WKY大鼠作为对照组。测定大鼠收缩压、血糖、三酰甘油、胆固醇及胰岛素水平，计算稳态模型评价的胰岛素抵抗指数（HOMA-IR）。禁食12h后，模型组予以腹腔注射链脲菌素（STZ）35mg／kg，对照组予以相同剂量的柠檬酸缓冲液。注射STZ72h后测随机血糖，以血糖≥16．7mmol／L为造模成功。观察8周后模型组与对照组的肾质量指数、收缩压、血脂、尿蛋白排泄以及肾脏病理变化情况。结果SHR大鼠高糖高脂饲料喂养2周后，与对照组相比，体质量、血脂、血糖均显著增加（均P〈0．05），HOMA—IR也显著升高（5．03±0．38比2．61±0．34，P〈0．05）。8周后，模型组大鼠多尿、多饮、体质量减轻，收缩压、血糖和糖化血红蛋白水平显著升高（P〈0．01）。尿蛋白量（24h）明显增加[（57．58＋16．54）mg／2dh比（5．35±1．90）mg／24h，P〈0．01]。肾质量指数（mg／g）也增加（P〈0．05），造模成功率为81．8％。病理改变为肾脏肥大，肾小球系膜基质增多，毛细血管基底膜增厚，足细胞空泡变性，足突消失，部分融合。结论联合高糖高脂饲料及小剂量STZ注射SHR大鼠成功制备2型糖尿病特征的动物模型，并诱导出糖尿病早期肾脏损害，为进一步研究2型糖尿病肾病发生机制和药物干预提供了简单实用的动物模型。

Objective To develop a model of type 2 diabetes with early renal injury on spontaneously hypertensive rats （SHR）. Methods The 6-week old SHR were fed with the diets enriched with sucrose （20%, W/W）, lard （10%, W/W）, cholesterol （2.5%, W/W） and chleo]ate （1%, W/W） to induce insulin resistance. Hyperglycemia was developed by intraperitonea｜ injection of streptozotocin （STZ, 35 mg/kg）. Wistar-Kyoto rats （WKY） were used as normal controls. Rats with plasma glucose （PGL） ≥ 16.7 mmol/L were diagnosed as diabetes. Eight weeks after the induction of diabetes, plasma triglyceride （TG）, cholesterol （CHO）, glucose, systolic pressure（SP）, 24-h urine protein excretion （Upro） were examined in all the rats, and the homeostasis model assessment of insulin resistance （HOMA-IR） was analyzed. Renal pathological changes were studied by immunohistochemical staining and electron microscope. Results After 2 weeks on the high sucrose and fat diets, the model rats exhibited significant increase in basal PGL, TG and CHO levels as compared to control rats （P〈0.05, respectively）. The insulin resistance was developed in model rats demonstrated by the higher HOMA-IR （5.03±0.38 vs 2.61±0.34, P〈0.05）. At the end of the experiment, model rats were associated with hypertension. Upro level was significantly increased in model rats compared with that in controls [（57.58±16.54） rag/24 h vs （5.35±1.90） rag/24 h, P〈0.01]. The kidney hypertrophy index （KWI） was significantly increased in the model rats compared to controls （P〈0.05）. Moreover, the diabetic model rats showed glomerular hypertrophy, foot process effacement, micro villous transformation, glomerular basement membrane （GBM） thickening. Conclusion A rat model is successfully established, which presents typical features of human type 2 diabetes and can be served as an ideal model to study the diabetic nephropathy.