【摘要】 目的　了解猪脑谷氨酸脱羧酶 (GAD)是否能预防非肥胖糖尿病 (NOD)小鼠的Ⅰ型糖尿病和影响其胰腺自身GAD6 5表达。方法　将GAD 5 0 μg与不完全弗氏佐剂 (FIA) 5 0 μl混合后给 32只4周龄NOD雌性小鼠腹腔注射 ,同时 19只单独注射FIA作为对照。每周测定体重、血糖 ,2 0周龄时处死小鼠 ,观察其病理、血清C肽和GAD抗体 ,并用逆转录PCR技术进行胰岛GAD6 5表达半定量。结果　 2 0周龄时 ,GAD组小鼠的糖尿病总发病率 (6 2 5 % )明显低于FIA组 (73 6 8% ) ,P <0 0 1,平均发病时间也晚 ;炎症分数明显降低 (0 0 83± 0 0 11vs 0 6 92± 0 0 5 4) ,炎症程度也明显减轻。GAD组的血清C肽水平 (2 41± 0 39) μg/L高于FIA组 (1 19± 1 2 2 ) μg/L ,但两组间GAD抗体阳性率差异无显著。GAD注射后胰腺GAD6 5mRNA表达水平明显高于FIA组。结论　GAD可预防NOD小鼠胰岛炎和糖尿病的发生 ,其机制可能与使胰岛GAD6 5表达增加诱导免疫耐受有关。更多还原

【Abstract】 Objective To study whether glutamic acid decarboxylase(GAD) purified from pig brain can prevent type Ⅰ diabetes in non obese diabetic(NOD) mice and influence the expression of GAD65 in islets. Methods GAD 50 μg mixed with Freund incomplete adjuvents(FIA) 50 μl was injected intreperitoneally(ip) into 32 NOD female mice at 4 weeks old, FIA was injected alone to 19 mice as control. All mice had blood glucose and body weight measured weekly. One single injection of cyclophosphamide(CY) was given to accelerate the diabetes at 8 weeks old. After death of the mice at 20 weeks old, the levels of C peptide and autoantibodies to GAD were detected and the pancreatic histopathology was observed too. The expression of GAD65 mRNA was measured using reverse transcriptase(RT) PCR technique. Results (1)GAD reduced the total incidence of type Ⅰ diabetes to 6 25% as compared with the FIA group(73.68%,P<0.01) and delayed its onset time(4 weeks vs 1.5 weeks after CY acceleration).(2)The insulitis score and the severity of insulitis in GAD mice were lower than that of the FIA group(P<0.05).(3) The C peptide levels were higher significantly in GAD group as compared with the FIA group(P<0.05),but the prevalence of GAD antibody was no significantly different between the two groups.(4)The levels of expressing products in islets of GAD mice (1.616±0.146) were much higher than those of FIA mice(1.226±0.018,P<0.05). Conclusion GAD protected the NOD female mice from getting diabetes and insulitis. Its mechanism may be related to induction of immune tolerance by increasing the GAD65 expression in islets.更多还原