微囊化胰島作為小鼠生機性之人工胰臟

動物實驗已經證實胰島細胞移植，不僅能控制血糖，並能防止或改善糖尿病末期合併症。但是胰島細胞本身所含之免疫抗原性，仍然是胰島移植治療糖尿病之主要障礙。本研究利用微膠囊包埋技術，以一種半透膜將移植之胰島細胞與宿主免疫系統分開而能解決此問題。在實驗中利用0.1％膠原蛋白酵素（collagenase）的消化技術從大白鼠胰臟分離蘭氏小島，利用不同密度的Ficoll梯度離心法純化並在解剖顯微鏡下個別挑取，每隻大鼠可獲得238 ± 48胰島。在培養一至三天後，將這些蘭氏小島細胞懸浮於1.6％海藻酸鈉乳膠中，與1.2％氯化鈣混合使之膠化成為球形小滴後，再用0.02％聚多離銨與之反應，使微膠囊粒表面形成一層透明半透膜，此微囊直徑小於1 mm。此微膠囊化之蘭氏小島經體外培養每一胰島所分泌胰島素（insulin）量是1.5 ± 0.2毫單位/hr。包埋之蘭氏小島利用H.E及aldehyde-fuchsin染色組織切片檢查得證實仍具生機功能。體外培養後將600至800個包埋胰島移植於鏈球霉素（streptozotocin）所引起糖尿病但免疫能力完整之老鼠腹腔內，可將由CDF1小鼠原有之高血糖濃度350 mg/dl，降至100 mg/dl，並維持正常血糖達一月餘，種植同樣數目未包埋之對照組，僅能維持十天。經由本研究微囊包埋胰島方式，證明在不使用免疫排斥劑情況下，可使胰島細胞持久存活。

關鍵字

微囊包埋大鼠胰島；異種移植；生機性人工胰臟；糖尿病小鼠

並列摘要

Animal experiments have proven that islet transplantation can prevent or reverse retinal or renal complications associated with diabetes. However, the immunogenicity of islets, remains the major obstacle to islet transplantation as a therapy for diabetes. In this study, we addressed this problem by microencapsulation of islets in semipermeable membranes, thereby isolating them from the host immune system. Islets of Langerhans were isolated from rats by 0.1% collagenase digestion techniques. The islets were separated by Ficoll gradient and/or hand-picked with the aid of a dissecting microscope. Each rat pancreas yielded 238 ± 48 islets. These islets were encapsulated in 1 ml 1.6% sodium alginate solution and dropped into 1.2% calcium chloride solution, which caused them to gel. These gel droplets were further treated in a 0.02% polylysine solution and formed semipermeable microcapsules (MC). When these microencapsulated islets (mean diameter down to 1 mm or less) were incubated at 37℃, insulin could be detected in the medium, indicating that the MC membrane is permeable to insulin. Viable functions of the microencapsulated islets were assessed by histological examination using hematoxylin-eosine and aldehyde-fuchsin stain. The microencapsulated islets were implanted intraperitoneally into nonimmunosuppressed streptozocin-induced diabetic mice. Diabetes was reversed within 3 days, fasting plasma glucose levels dropped from a pretransplanted of 350 mg/dl to 110 mg/dl. The longest normoglycemic period in these mice was more than 1 month, which was markedly longer than the normoglycemic period obtained by nonencapsulated islets. This study demonstrated that encapsulation of pancreatic islets in semipermeable membranes can prolong xenograft survival in the absence of immunosuppression.

並列關鍵字

Microencapsulated rat islets ； Bioartificial pancreas ； Xenotransplantation ； Diabetic mice

國際替代計量

微囊化胰島作為小鼠生機性之人工胰臟

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