链脲佐菌素对大鼠胰岛β细胞结构及超微结构损伤的特点

Structural and Ultramicrostructural Changes of Beta-cells Induced by Streptozotocin in Rats

目的:研究链脲佐菌素(STZ)对大鼠胰岛β细胞结构及超微结构损伤的特点方法:大鼠随机分为两组,正常对照组(NC组),STZ组各10只大鼠。SIZ(70 mg/kg)一次性腹腔内注射以诱发糖尿病。实验分组时及STZ注射后每3天测大鼠血糖,称体重1次,实验结束时处死动物,取部分胰腺组织进行生化指标检测,部分胰腺组织行HE染色及制备电镜标本。结果:STZ使大鼠血糖明显升高,SIZ组胰腺组织内MDA水平(1.22±0.14)nmol/mgprot,较NC组MDA水平(0.57±0.04)nmol/mgprot明显升高(P<0.05);同时STZ组胰腺组织内GSH含量(16.54±1.10)mg/gprot,较NC组GSH含量(25.46±0.62)mg/gprot明显降低(P<0.05);GSH-Px活性明显降低(P<0.05)。HE染色见STZ组胰岛呈退行性及坏死样改变,胰岛萎缩;电镜下观察部分胰岛β细胞坏死,部分胰岛β细胞线粒体肿胀,内质网扩张,脂肪滴沉着,髓鞘样小体形成等。NC组胰岛HE染色及透射电镜下观察结构正常。结论:STZ通过氧化应激损伤胰岛β细胞,导致其结构和超微结构的破坏。

Objective： To explore the structural and uttramicrostructural changes of pancreatic β-ceils induced by streptozotocin in rats. Methods：Twenty rats were randomly divided into two groups： Normal control （NC） group and STZ group. STZ （70 mg/kg J was giwm intraperitoneally after animals had been fasted for 12 hours. Blood glucose levels were measured before and every three day after STZ injection. MDA,GSH levels and GSH-Px activities an pancreatic homogenates were determined. Pancreatic beta-cells were examined by using hematoxylin and eosin staining and transmission electron mieroseopy（TEM）, Results：STZ induced a significant increase in blood glucose levels. a significant increase in MDA levels （P〈0.05） . a significant decrease in GSH levels （P〈O.05） and GSH-Px activities （P〈O.05） in pancreatic homogenates. The histological stndy showed degenerative and necrotic changes of islet cells and shrinking of islets in STZ-treated rats. The TEM study with ST-Z-treated rat beta-cells demonstrated dilated endoptasmie reticulum; swollen and vacuotization of mitochondria. There were fatty drops and concentric dense laminas accumulated in the cytoplasm of beta-cells of STZ-treated rats. Conclusions：Administration of STZ to rats results in the structural and uhramicrustructuml changes of pancreatic β-cells through increasing the severity of oxidative stress in oanereatic tissues.