2型糖尿病大鼠模型的建立及其氧化应激特征分析

Establishment of type 2 diabetic rat model and analysis of its oxidative stress characters

目的建立一种与人类2型糖尿病发病特点相似的动物模型。方法将体质量180～220g的SD雄性大鼠30只随机分为5组,分别为:对照组、高脂高糖组(HH)、高脂高糖+60Co照射组(HH+R)、高脂高糖除抗氧化剂组(HH-AntiO)及高脂高糖除抗氧化剂+60Co照射组(HH+R-AntiO)。HH+R组和HH+R-AntiO组于实验第15、30、60天给予剂量为4Gy的60Co-γ射线全身照射。在指定时间点检测各处理组动物的氧化应激指标,实验第60天时进行静脉糖耐量实验。大鼠出现胰岛素抵抗后,腹腔注射链脲佐菌素(20mg/kg),每周1次,连续4周,大鼠诊断为2型糖尿病后,进行胰腺灌流实验检测胰岛B细胞功能。整个实验进行过程中监测血糖和胰岛素水平。结果各组动物在不同时间点出现不同程度的氧化损伤改变。第60天时,除HH组外,其余各组动物均出现胰岛素抵抗。结合小剂量链脲佐菌素注射后,大鼠出现比较稳定的中度高血糖,其中HH-AntiO组大鼠对葡萄糖刺激的反应最为接近2型糖尿病患者胰岛素分泌的两相性特点;同时胰腺中胰岛素也有一定的贮存量,约为对照组的40%。结论与遗传因素在发病过程中起主导作用的转基因大鼠模型相比,本研究建立的大鼠2型糖尿病模型能更好地观察环境因素对机体的影响,可以用于预防和治疗2型糖尿病的药物研究。

Objective To develop a rat model of type 2 diabetes mellitus that presents with syndromes close to those in human. Methods Thirty male SD rats （weighted 180-220 g） were equally randomized into five groups： control group, high fat and high sugar group （HH group）, high fat and high sugar plus ^60Co-γ exposure group （HH＋R）, high fat and high sugar and antioxidant deprival group （HH-AntiO group）, high fat and high sugar and antioxidant deprival plus ^60Co-γ exposure group （HH＋R-AntiO group）. The HH＋R and HH＋R-AntiO groups underwent ^60Co-γ total body irradiation at a dosage of 4 Gy on days 15, 30 and 60. For these five groups, oxidative stress indexes were detected at pre-designed time points, and intravenous glucose tolerance test （IVGTT） was conducted on day 60. After develo pment of insulin resistance in the rats, 20 mg/kg streptozocin （STZ） was injected intraperitoneally once a week for four weeks. After the rats were diagnosed as type 2 diabetes mellitus, perfusion pancreas technique was used to evaluate the function of insular B Cell. The level of blood glucose and serum insulin was monitored during the whole experimental process. Results Various degrees of oxidative damage was presented in these groups at different time points. On day 60, insulin resistance was found in rats except for HH group rats. After low-dose STZ injection, rats stably showed moderate hyperglycemia. The responsiveness to glucose in HH-AntiO group rats was closest to the two-phase characteristic of insulin secretion in human diabetics. The pancreatic insulin storage of HH-AntiO group rats was about 40% the amount of control rats. Conclusion Type 2 diabetes mellitus model established in this study can be more helpful in observing the effects of environment factors on body than transgenic model where genetic factor plays main role in the pathogenesis. This model can also be used to investigate the medicine for preventing and treating type 2 diabetes mellitus.