【摘要】 目的:探讨链脲佐菌素(STZ)诱导的糖尿病树鼩胰岛β细胞再生与Bax、Bcl-2表达的关系。方法:将32只树鼩随机分为正常对照组和STZ处理组。根据血糖的变化将STZ处理组又分为4个亚组:血糖正常组(A组)、血糖先升高后恢复正常组(B组)、糖耐量减低组(C组)、糖尿病组(血糖≥11.1mmol/L,D组)。苏木精—伊红(HE)染色观察各组胰岛细胞形态、数量,免疫组织化学染色法检测各组树鼩胰腺胰岛素、胰腺十二指肠同源框蛋白1(Pdx-1)、神经元素蛋白3(Ngn3)、Bax、Bcl-2的表达。结果:与正常对照组相比,STZ处理组胰岛素、Pdx-1、Ngn3、Bcl-2蛋白表达量均明显降低(均P<0.05);A组、B组胰岛素、Pdx-1、Ngn3、Bcl-2表达均高于C组和D组,而Bax表达低于C组和D组(均P<0.05)。HE染色结果显示,B组胰岛细胞与正常对照组较为相似,数量较多,而D组胰岛细胞出现萎缩,数量显著减少。胰岛Pdx-1、Ngn3与Bcl-2蛋白表达呈正相关关系(r=0.830,r=0.803;均P<0.001),而与Bax蛋白表达呈负相关关系(r=-0.678,r=-0.643;均P<0.001)。结论:STZ诱导的糖尿病树鼩血糖恢复正常的机制可能是通过上调胰腺发育相关的转录因子Pdx-1、Ngn3的表达,同时调节Bcl-2和Bax的表达,使得胰岛β细胞数量及胰岛素分泌增加,从而实现胰岛再生,改善血糖代谢。更多还原

【Abstract】 Objective:To investigate the relationship between pancreaticβcell regeneration and the expressions of Bax and Bcl-2 in streptozotocin(STZ)-induced diabetic tree shrews.Methods:32tree shrews were randomly divided into a control group and a STZ group.The STZ group were divided into 4subgroups:group A in which the animals maintained a proper blood glucose level,group B in which the animals had an increased blood glucose at first and then returned to normal,group C in which the animals had impaired glucose tolerance,and group D(diabetes group,blood glucose≥11.1 mmol/L).The morphology and quantity of islet cells were observed by hematoxylin-eosin(HE)staining.The expression of pancreatic insulin,pancreatic and duodenal homeobox factor 1(Pdx-1),neural element protein 3(Ngn3),Bax and Bcl-2 in pancreatic tissues of tree shrews were observed by immunohistochemistry.Results:Compared with the control group,the expressions of insulin,Pdx-1,Ngn3 and Bcl-2 protein in STZ group were significantly decreased(P <0.05).The expressions of insulin,Pdx-1,Ngn3 and Bcl-2 in group A and group B were higher,while the Bax expression was lower than those in group C and group D(P <0.05).The morphology of islet cells in group B was similar to that in control group,whereas the islet cells shrank in group D,and the number was notably decreased.The expression of Pdx-1and Ngn3 was negatively correlated with Bax(r=-0.678,r=-0.643;both P <0.001),and was positively correlated with Bcl-2 (r=-0.830,r =-0.803;both P <0.001).Conclusion:The elevated blood glucose level in STZ-induced diabetic tree shrews returned to normal might be related to the up-regulation of Pdx-1and Ngn3,and the modulation of Bcl-2 and Bax expression,causing the increased islet cells number and insulin secretion,and then achieving islet regeneration and glucose metabolism improvement.更多还原