不同剂量链脲佐菌素诱导C57BL/6小鼠1型糖尿病模型的复制与iNKT细胞的检测

目的  腹腔注射不同剂量链脲佐菌素（STZ）于雌性C57BL/6小鼠，诱导建立与人类1型糖尿病相似的动物模型，研究最适链脲佐菌素（STZ）建模剂量。方法  35只雌性C57BL/6小鼠随机分为正常对照组（n =5）和模型一、二、三组（STZ剂量分别为40、50和60 mg/kg），每组10只。模型组连续5 d腹腔注射不同剂量STZ，测定注射前、注射后1、2、3、4和5周的空腹血糖和体重，小鼠胰岛素自身抗体（IAA）阳性率，观察小鼠饮食、饮水和排尿情况。流式细胞技术（FACS）分析血和脾细胞悬液中恒定自然杀伤T细胞（iNKT）细胞比例；HE染色观察胰岛病理。结果  与对照组比较，模型三组饮水量、进食量和排尿量增加，体重减轻。与对照组比较，模型三组血糖变化明显，注射STZ后第1周迅速升高，第4周达高峰，随后下降，差异有统计学意义（P <0.05）。与对照组比较，模型组3组胰岛萎缩，胰岛细胞不规则，数目减少。模型二组和模型三组IAA阳性率分别达到30%和90%。与对照组比较，模型三组外周血CD4+NK1.1+淋巴细胞和脾CD4+NK1.1+淋巴细胞比例减少，差异有统计学意义（P <0.05）。结论  诱导建立雌性C57BL/6小鼠1型糖尿病模型的最适STZ剂量为60 mg/kg。

Study on model of type 1 diabetes in C57BL/6 mice induced by different dose of streptozotocin and detection of iNKT cell

Objective To establish an animal model of type 1 diabetes mellitus similar to human and study the modeling optimal dose of streptozotocin (STZ). Methods A total of 35 female C57BL/6 mice were randomly divided into control group (n = 5) and model group1, 2, 3 (the dose of STZ was 40 mg/kg, 50 mg/kg, 60 mg/kg respectively) with 10 mice in each group. By intraperitoneal injection to the model group of different doses of STZ for 5 days. Blood glucose and body weight before and 1, 2, 3, 4, 5 weeks after injection were determined. Possitive rate of insulin autoantibodies (IAA) in mice were determined. The conditions of mice eating, drinking and urination were observed. Flow cytometry (FACS) analysis was used to analyze the proportion of iNKT cells in blood and spleen cell suspension. HE staining was used to observe the pathological changes of pancreatic islets. Results Compared with the control group, the amount of drinking water, food intake and urine volume were significantly increased, and the weight was significantly reduced in model group 3. Compared with the control group, the change of blood glucose in model group 3 was obvious, and the first week after injection of STZ the blood glucose increased rapidly, and reached its peak in the fourth week and then decreased, the difference was significant (P < 0.05). Compared with the control group, the three groups of model group were significantly decreased in the number of islet cells,. The positive rates of IAA in model group 2 and 3 were 30% and 90% respectively. Compared with the control group, the proportion of CD4+ NK1.1+ lymphocytes in peripheral blood and CD4+ NK1.1+ lymphocytes in spleen were significantly decreased in model group 3, and the differences were significant (P < 0.05). Conclusions The optimal dose of STZ is 60 mg/kg in inducing and establishing of type 1 diabetes mellitus in female C57BL/6 mice.