诱导构建最佳类似人类2型糖尿病大鼠的造模方式

Establishing methods for constructing rat models of type 2 diabetes mellitus which are the most similar to human beings

目的:观察注射链脲佐菌素大鼠在给予高脂高糖不同时间后血糖、血脂、糖耐量、胰岛素敏感性等的变化情况,以寻求最佳类似人类2型糖尿病的大鼠造模方式。方法:实验于2003-01/12在福建中医学院中心实验室及福建省中医药研究院血液流变室完成。选择雌性Wistar大鼠56只,适应性喂养1周后,随机分为7组,正常组、高脂高糖2,4,6周组、普食6周组、先注射链脲佐菌素组和单纯高脂高糖组各8只。①正常组:灌胃生理盐水。②高脂高糖2周组:先灌胃高脂高糖乳剂14d后+注射链脲佐菌素30mg/kg2次。③高脂高糖4周组:先灌胃高脂高糖乳剂28d后+注射链脲佐菌素30mg/kg2次。④高脂高糖6周组:先灌胃高脂高糖乳剂42d后+注射链脲佐菌素30mg/kg1次。⑤普食6周组:灌胃生理盐水42d后+注射链脲佐菌素30mg/kg2次。⑥先注射链脲佐菌素组:先注射链脲佐菌素(30mg/kg)2次后+灌胃高脂高糖乳剂42d。⑦单纯高脂高糖组:灌胃高脂高糖乳剂42d,不注射链脲佐菌素。腹腔注射链脲佐菌素30mg/kg2次间隔4d,注射前均禁食不禁水14h。每日高脂高糖乳剂/生理盐水灌胃量均为10mL/kg。各组均自由进食普通饲料。实验过程中检测各组随机血糖及空腹血糖、葡萄糖耐量;结束后禁食不禁水16h,腹主动脉取血,测量各组大鼠的空腹胰岛素、血脂,同时取胰腺作病理检查。口服葡萄糖糖耐量试验诊断标准:大鼠禁食12h服糖后血糖峰值16.7mol/L、且120min血糖11.1mmol/L的大鼠确定为糖尿病。结果:56只大鼠全部进入结果分析,无脱失。①各组大鼠血糖水平比较:高脂高糖6周组大鼠在注射链脲佐菌素后空腹血糖显著高于正常组[(12.20±0.87),(3.90±0.27)mmol/L(P<0.01)],随机血糖也显著高于正常组[(27.31±1.82),(5.01±0.41)mmol/L(P<0.01)],均达到糖尿病大鼠诊断标准,提示造模成功。其余各组大鼠血糖值均未达到糖尿病大鼠诊断标准。②口服葡萄糖糖耐量试验结果:高脂高糖6周组大鼠75%出现糖耐量异常,0.5h血糖达到(17.51±1.23)mmol/L,超过16.7mmol/L,2h后下降为(6.83±0.89)mmol/L,未回复到正常水平。然而先注射链脲佐菌素组在注射链脲佐菌素后空腹血糖为(5.98±1.59)mmol/L,随机血糖为(12.53±4.03)mmol/L,未达到糖尿病大鼠诊断标准。③各组大鼠实验后血脂水平比较:除高脂高糖2周组外,其余各组大鼠的三酰甘油水平均显著高于正常组(P<0.01)。高脂高糖6周组和单纯高脂高糖组大鼠的总胆固醇水平升高最为显著。结论:先高脂高糖6周后加腹腔注射链脲佐菌素30mg/kg1次,可成功制备空腹和随机血糖均升高,且糖耐量低减、高血脂的类似人类2型糖尿病的大鼠模型。

AIM： To observe the changes of blood glucose, blood lipids, glucose tolerance and insulin sensitivity in rats injected by streptozotocin at different time of hypedipid and hyperglucose, so as to seek the best methods for establishing rat models of type 2 diabetes mellitus which are similar to human beings. METHODS： The experiment was carried out in the central laboratory of Fujian College of Traditional Chinese Medicine and the hemorrheogical room of Fujian Institute of Traditional Chinese Medicine between January and December 2003. Fifty-six healthy female Wistar rats were randomly divided into 7 groups with 8 rats in each group after 1-week adaptive feed： normal control group （administration with normal saline）, enriched diet 2, 4 and 4-week groups （fore-administrated with enriched diet for 14, 28 and 42 days respectively, and then injected with 30 mg/kg streptozotocin for twice）, common diet 6-week group （fore-administrated with normal saline for 6 weeks, and then injected with 30 mg/kg streptozotocin for twice）, fore-infection with streptozotocin group （fore-infected with 30 mg/kg streptozotocin for twice, and then administrated with enriched diet for 2 weeks）, pure enriched diet group （fore-administrated with enriched diet for 6 weeks, not injected with streptozotocin）. The two intraperitoneal injections of streptozotocin were given with a 4-day interval, and the rats were fasted for 14 hours before injection, the daily perfused volume was 10 mL/kg, all the rats could eat common diet freely. During the experiment, the fasting and non-fasting blood glucose and glucose tolerance were detected; After the experiment, the rats were fasted for 16 hours, and then blood samples were taken from abdominal aorta to determine the fasting insulin and blood lipids, pancreas was also removed at the same time for pathological examination. Diagnostic standards of oral glucose tolerance test （OGTT）： The rats with the peak value of blood glucose of 16.7 mol/L after fasted for 12 hours, and the 120-minute blood glucose of 11.1 mmol/L were diagnosed to have diabetes mellitus. RESULTS： All the 56 rats were involved in the analysis of results without deletion. ① Comparison of blood glucose levels among the groups： After injection of streptozotocin, the fasting blood glucose level in the enriched diet 6-week group was significantly higher than that in the normal control group [（12.20±0.87）, （3.90±0.27） mmol/L, P 〈 0.01], and non-fasting glucose was also significantly higher than that in the normal control group [（27.31±1.82）, （5.01±0.41） mmol/L, P 〈 0,01], which all reached the diagnostic standards of diabetes mellitus, indicating that models were successfully established. The blood glucose levels in the other groups all did not reached the diagnostic standards of diabetes mellitus. ② OGTY results： 75% of the rats in the enriched diet 4-week group presented glucose tolerance impairment, 0.5-hour blood glucose reached （17.51±1.23） mmol/L, higher than 16.7 mmol/L, it decreased to （6.83±0.89） mmol/L after 2 hours, did not recovered to the normal level. In the fore-infection with streptozotocin group, the fasting blood glucose was （5.98±1.59） mmol/L, non-fasting blood glucose was （12.53±4.03） mmol/L, which did not reached the diagnostic standards of diabetes mellitus. ③Comparison of blood lipids after experiment among the groups： Except the enriched diet 2-week group, the level of triglyceride was significantly higher in the other groups than in the normal control group （P 〈 0.01）. The level of total cholesterol increased the most significantly in the enriched diet 6-week group and pure enriched diet group. CONCLUSION： Abdominal injection with 30 mg,/kg streptozotocin once after It will succeed to develop DM rats model which similar to human 2- DM with enriched diet for 6 weeks can successfully establish rat models of type 2 diabetes mellitus with increased fasting and non-fasting blood glucose, glucose tolerance impairment and hyperlipidemia, which are similar to human beings.