NOD小鼠胰岛的分离及其在体内外的生物学特性

摘要

目的 建立分离纯化非肥胖性糖尿病(NOD)小鼠胰岛的方法,并对其体内外生物学特性进行研究.方法 采用改良的胶原酶消化结合Ficoll密度梯度离心方法,分离纯化NOD小鼠胰岛.应用体外糖刺激实验检测分离纯化的胰岛功能,以及通过监测移植小鼠的血糖、体重变化及糖耐量实验对移植胰岛的体内生物学功能进行分析,并通过HE染色和免疫荧光染色检测肾被膜下移植胰岛的存活情况.结果 胰岛产率为(116 ± 12)个胰岛/胰腺,纯度>90%.体外糖刺激实验结果显示,NOD小鼠胰岛的糖刺激胰岛素释放水平明显低于KM小鼠胰岛.胰岛移植实验显示,移植胰岛能有效改善糖尿病小鼠的血糖、体重和糖耐量,但改善作用一般仅能维持2周左右.HE染色和免疫荧光染色结果显示,肾被膜下可见胰岛素阳性的胰岛细胞团,并且在残存的移植胰岛细胞团周围存在大量淋巴细胞浸润.结论 通过改良的小鼠胰岛分离方法可由NOD小鼠分离得到大量较高纯度的胰岛,可用于今后探索如何阻断自身免疫损伤保护移植胰岛的研究.%Objective This study was conducted to establish a stable and highly efficient method for isolation and purification of pancreatic islets from NOD mice and to evaluate their characteristics in vitro and in vivo. Methods The is-lets were isolated from mouse pancreas using modified collagenase digestion and Ficoll density gradient centrifugation. The endocrine secretory function was assessed by insulin secretion in either low or high dose glucose stimulation. To evaluate the function of the graft,body weight and blood glucose were monitored,and IVGTT was performed. In addition,to assess sur-vival of the implanted islets,Pathology using HE staining and insulin immunostaining of the graft were performed. Results The average islet yield was 116 ± 12 islets/pancreas and purity was higher than 90%. Compared with islets from Kunming mice,the islets isolated from NOD mice were poorly responsive to glucose challenge. Blood glucose levels and body weight changes of the islet-transplanted diabetic mice were significantly improved compared with the sham-operated mice. In addi-tion,blood glucose levels in vivo after an IVGTT also significantly improved. However,these improvements were only main-tained for 2 weeks. Furthermore,HE staining and immunostaining assays demonstrated that there were insulin-positive cell clusters and lymphocyte infiltration in the graft-bearing kidney. Conclusions A large number of quality islets can be isola-ted and purified from NOD mice by using the modified mouse islet isolation method, which can be used to develop thera-peutic strategies to protect transplanted islets from rejection and autoimmune attack.