多次小剂量STZ处理建立糖尿病大鼠模型及EGF与Gastrin联合应用对胰岛素分泌的影响

Repeated low-dose STZ treatment for diabetic rats model and EGF and Gastrin combined application effect on insulin secretion

目的通过多次小剂量STZ处理建立糖尿病大鼠模型,观察EGF/Gastrin联合应用对模型大鼠胰岛功能的影响。方法采用35mg·Kg-1腹腔注射STZ-枸橼酸钠缓冲液,每周1次,连续4周,建立大鼠糖尿病模型。采用生化分析和组织染色的方法观察血糖和胰岛细胞的改变。成模大鼠随机分为三组:Insulin治疗组,EGF/Gastrin联合治疗组及DM对照组。EGF/Gastrin组给予EGF(1μg·Kg-1)/Gastrin(3μg·Kg-1),每日1次皮下注射,连续14日;Insulin组给予长效胰岛素2U/d,连续14日;DM对照组及正常对照组给予枸橼酸钠缓冲液。观察血浆中胰岛素和C肽的改变,评估胰岛细胞功能。结果 35只实验组大鼠中有33只血糖值≥11.1mmol·L-1,占总数的94%。Insulin组大鼠和EGF/Gastrin组大鼠血糖值同DM组相比显著降低。DM组中血清胰岛素及C肽含量显著低于正常对照组(P<0.05),而Insulin组及EGF/Gastrin组均显著高于DM组(P<0.05)。组织学结果观察发现,成模大鼠的胰岛数量明显减少,分布不均匀并出现不同程度的萎缩,出现空泡变性。Insulin免疫组织化学染色结果显示,成模大鼠胰岛内Insulin染色阳性的细胞明显减少;且残存胰岛β细胞Insulin染色强度低于正常对照组,Insulin组及EGF/Gastrin组大鼠胰岛中Insulin表达细胞明显增多,有部分细胞呈强阳性表达。结论 EGF和Gastrin联合应用能够促进糖尿病大鼠胰岛功能的恢复。

Objective Through multiple low-dose STZ treatment to establish diabetic rats model,observe the EGF/ Gastrin effect on model rats with islet function. Methods diabetic rats model was established by 35 mg ·Kg^-1 intrap- eritoneal injection of STZ-sodium citrate buffer, 1 time each week for four weeks. The biochemical analysis and tissue staining method to observe the change of blood sugar and islet cell. The diabetic rats were randomly divided into DM group,Insulin therapy group（Insulin group） and EGF/Gastrin combined therapy group. EGF/Gastrin group was trea- ted with EGF （1 μg·Kg^-1 ）and gastrin （3μg·Kg^-1） for 14 days subcutaneously. Insulin group was treated with long-acing insulin（2 U · d^-1 ） for 14 days. The change of plasma insulin and C peptide were observed and function of islet cells was evaluated. Results Blood glucose test showed that there were 33 rats presented higher glucose than 11.1 mmol · L-1 in 35 rats. It took 94% of the total. Blood glucose in Insulin and EGF/Gastrin group rats significantly reduced compared with DM group. Serum Insulin and C peptide concentration in DM group was significantly lower than normal control group（P〈0.05）,and Insulin and EGF/Gastrin group were significantly higher than that of DM group （P〈0.05）. Histological results showed that islet number of diabetic rat decreased significantly, and appeared vacuolar degeneration, immunohistochemical staining showed that Insulin positive cells decreased significantly in diabetic rat is- let, and residual islet beta cells intensity is lower than the normal control group. Insulin group and EGF/Gastrin Insulin expression in rat islet cells increased obviously,there are some cells was strong positive expression. Conclusion EGF and Gastrin combined application can enhance the recovery of diabetic rats islet function.