高脂饮食诱导的2型糖尿病模型小鼠的生化及病理分析
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摘要
目的分析高脂饮食结合小剂量链脲佐菌素(STZ)注射方法制备的2型糖尿病(T2DM)模型小鼠的生化及病理改变。方法将C57BL/6J实验小鼠随机分成3组:正常饮食组(NC组),高脂饮食组(HC组)和高脂饮食加STZ组(HC+STZ组)。HC+STZ组高脂高糖饲料饲养1个月后,按40 mg/kg剂量腹腔注射STZ,24 h后再注射1次;HC组高脂高糖饲养,NC组一直用普通饲料饲养,两组注射等量的柠檬酸缓冲液作为对照。注射STZ后每周测定空腹血糖,持续4周;1个月后进行口服葡萄糖试验(OGTT);然后处死小鼠,对血浆进行相关的生化检测,免疫组化检测胰岛形态结构,病理分析肝脏,肾脏的结构形态情况。结果 (1)注射STZ 1周后,有75%的小鼠空腹血糖超过阈值(13.89 mmol/L);2周后除1只小鼠死亡外,其余小鼠空腹血糖均超过阈值,造模成功率为91.3%;HC组空腹血糖比NC组略有升高,但尚在正常值范围内;(2)高脂饮食的HC+STZ组和HC组小鼠体质量均显著高于NC组(P<0.01),STZ注射后体质量增加不明显;(3)OGTT结果显示,HC+STZ组口服葡萄糖后0.5~2 h的血糖都显著高于NC组和HC组(P<0.01);HC组0.5~2 h的血糖也高于NC组,但只有1.5 h血糖有显著差异;HC+STZ组AUC(曲线下面积)显著高于NC组或HC组(P<0.01);HC组AUC略高于NC组(P<0.05);(4)生化检测显示,HC+STZ组血浆中的肌酐(CR)含量显著高于NC组(P<0.01)和HC组(P<0.05);(5)胰岛的免疫组化染色显示,HC组胰岛结构完整,细胞排列规整,胰岛素的分泌较NC组减少;HC+STZ组胰岛萎缩,细胞排列紊乱,可见许多空泡状和纤维化结构,胰岛素的分泌明显减少。病理检测显示肝脏有轻度的脂肪肝,肾脏的形态结构未见明显改变。结论高脂饮食结合低剂量STZ多次注射制备的T2DM模型小鼠与人类T2DM有非常相似的病理结构和生化改变,伴有脂肪肝等并发症。
Objective To analyze the biochemical and pathological changes in mice with type 2 diabetes mellitus(T2DM)induced by high-fat diet combined with low-dose streptozotocin(STZ) injections. Methods C57BL/6J mice were divided randomly into normal control group(NC group), high-fat diet group(HC group) and high-fat diet plus STZ group(HC+STZ group). The mice were fed on normal chow or a high-fat diet for 1 month before two introperitoneal injections of STZ(40 mg/kg) or citrate buffer with an interval of 24 h as appropriate. Fasting blood glucose(FBG) was detected every week for 4 weeks,and oral glucose tolerance test(OGTT) was performed one month after the injections, after which the biochemical profiles, islet and liver were evaluated by immunohistochemical and pathological analysis. Results In HC+STZ group, FBG was above the cutoff value(13.89 mmol/L) in 75% of the mice at 1 week after STZ injections and in all the mice at two weeks except for the death of 1 mouse, with a success rate of modeling of 91.3%. FBG in HC group, though slightly higher than that in NC group,remained normal(6.8 mmol/L). The body weight in HC+STZ and HC groups was significantly higher than that in NC group after feeding but without obvious increases after the injections(P<0.01). Blood glucose in HC+STZ group at 0.5 to 2 h after OGTT and the area under curve(AUC) were higher than those in NC and HC groups(P<0.01); the AUC in HC group was a also higher than that in NC group(P<0.05). Plasma creatinine was significantly higher in HC+STZ group than in NC(P<0.01)and HC(P<0.05) groups. Insulin secretion by the islets decreased obviously in HC+STZ and HC group. The mice in HC+STZ group showed atrophy, fibrosis, and vacuolization in the islets with mild fatty liver but no visible renal pathologies.Conclusion High-fat diet and low-dose STZ injections can induce T2 DM in mice with very similar biochemical and pathological changes to human T2 DM and with such complications as fatty liver.
Objective To analyze the biochemical and pathological changes in mice with type 2 diabetes mellitus(T2DM)induced by high-fat diet combined with low-dose streptozotocin(STZ) injections. Methods C57BL/6J mice were divided randomly into normal control group(NC group), high-fat diet group(HC group) and high-fat diet plus STZ group(HC+STZ group). The mice were fed on normal chow or a high-fat diet for 1 month before two introperitoneal injections of STZ(40 mg/kg) or citrate buffer with an interval of 24 h as appropriate. Fasting blood glucose(FBG) was detected every week for 4 weeks,and oral glucose tolerance test(OGTT) was performed one month after the injections, after which the biochemical profiles, islet and liver were evaluated by immunohistochemical and pathological analysis. Results In HC+STZ group, FBG was above the cutoff value(13.89 mmol/L) in 75% of the mice at 1 week after STZ injections and in all the mice at two weeks except for the death of 1 mouse, with a success rate of modeling of 91.3%. FBG in HC group, though slightly higher than that in NC group,remained normal(6.8 mmol/L). The body weight in HC+STZ and HC groups was significantly higher than that in NC group after feeding but without obvious increases after the injections(P<0.01). Blood glucose in HC+STZ group at 0.5 to 2 h after OGTT and the area under curve(AUC) were higher than those in NC and HC groups(P<0.01); the AUC in HC group was a also higher than that in NC group(P<0.05). Plasma creatinine was significantly higher in HC+STZ group than in NC(P<0.01)and HC(P<0.05) groups. Insulin secretion by the islets decreased obviously in HC+STZ and HC group. The mice in HC+STZ group showed atrophy, fibrosis, and vacuolization in the islets with mild fatty liver but no visible renal pathologies.Conclusion High-fat diet and low-dose STZ injections can induce T2 DM in mice with very similar biochemical and pathological changes to human T2 DM and with such complications as fatty liver.
引文
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[12]余传林,朱正光,雷林生,等.链脲佐菌素糖尿病模型动物血糖及体征动态变化的研究[J].南方医科大学学报,2008,28(1):132-3.
[2]Kim JO,Lee GD,Kwon JH,et al.Anti-diabetic effects of new herbal formula in neonatally streptozotocin-induced diabetic rats[J].Biol Pharm Bull,2009,32(3):421-6.
[3]Gilbert ER,Fu Z,Liu D.Development of a nongenetic mouse model of type 2 diabetes[J].Exp Diabetes Res,2011:416254.
[4]Sharma AK,Bharti S,Ojha S,et al.Up-regulation of PPARγ,heat shock protein-27 and-72 by naringin attenuates insulin resistance,β-cell dysfunction,hepatic steatosis and kidney damage in a rat model of type 2 diabetes[J].Br J Nutr,2011,106(11):1713-23.
[5]Poucher SM,Cheetham S,Francis J,et al.Effects of saxagliptin and sitagliptin on glycaemic control and pancreaticβ-cell mass in a streptozotocin-induced mouse model of type 2 diabetes[J].Diabetes Obes Metab,2012,14(10):918-26.
[6]Donath MY,Shoelson SE.Type 2 diabetes as an inflammatory disease[J].Nat Rev Immunol,2011,11(2):98-107.
[7]Jagannathan-Bogdan M,Mcdonnell ME,Shin H,et al.Elevated proinflammatory cytokine production by a skewed T cell compartment requires monocytes and promotes inflammation in type 2 diabetes[J].J Immunol,2011,186(2):1162-72.
[8]Cooperstein SJ,Watkins D.Action of toxic drugs on islet cells.In:Cooperstein[C]//SJ,new york:academic press,1981:p387-425.
[9]Ho RS,Aranda CG.In vivo and in vitro glucose metabolism in a low dose streptozotocin rat model of non insulin dependent diabetes.In:Shafrir[C]//E,1988:p288-94.
[10]成细华,喻嵘,明霞,等.2型糖尿病合并非酒精性脂肪肝动物模型的建立[J].胃肠病学和肝病学杂志,2011,20(1):77-80.
[11]宋立江,刘长青,郭金铭,等.链脲佐菌素致小鼠糖尿病模型影响条件的实验研究[J].实用预防医学,2008,15(5):1592-3.
[12]余传林,朱正光,雷林生,等.链脲佐菌素糖尿病模型动物血糖及体征动态变化的研究[J].南方医科大学学报,2008,28(1):132-3.