海藻酸钠-氯化钡微囊在大鼠同种异体胰岛移植中免疫隔离效应的研究

A preliminary observation on the immunoisolation effect of the microencapsulated SD rat islet grafts by barium-alginate membrane

分别将游离胰岛和微囊化胰岛移植于链脲佐菌素(STZ)诱导的糖尿病大鼠肾包膜下及腹腔内,在实验终点取各组大鼠脾细胞,采用混合胰岛淋巴细胞培养方法及ELISA法检测培养上清液中IL-2和IFN-γ含量,观察胰岛移植后大鼠脾脏T淋巴细胞对同种异体胰岛的应答能力。结果表明,微囊化胰岛移植组糖尿病大鼠和游离胰岛移植组糖尿病大鼠胰岛有功能存活时间分别为>6周和(6.6±2.07)d。微囊化胰岛移植组的刺激指数(SI)与正常对照组比较差异无显著性,游离胰岛移植组SI和IL-2、IFN-γ活性显著高于微囊化胰岛移植组和正常对照组(P<0.05)。可见海藻酸钠-氯化钡微囊化胰岛可明显延长同种异体移植物的存活时间,在体外混合胰岛淋巴细胞培养反应体系中表现为免疫低应答性,具有较好的免疫隔离作用。

To investigate the mechanism of immunoisolation effect of the implanted barium alginate microencapsules containing SD rat islet grafts for the treatment of type 1 diabetes mellitus, the STZ-diabetic Wistar rats were transplanted intraperitoneally with the microencapsulated SD rat islet grafts or under the capsule of kidney with the free islet grafts. Mixed islet-lymphocyte co-cultivation and the determination of the IL-2 and IFN-γ contents in the culture supernatants by ELISA were used to evaluate the responses of the T lymphocytes in the spleen of the tansplanted rats to the allogeneic islets. The experimental results showed that the survival time of the microencapsulated islet grafts was more than 6 weeks, while that of the non-encapsulated islet grafts was (6.6±2.07) days. There was no significant difference in the stimulation indices(SI) between the microencapsulated group and the normal control group, but the SI and the activities of IL-2 and IFN-γ of the free islet graft group were significantly higher than those of the normal control group. Therefore, it was proved that the barium alginate membrane-microencapsulated islet grafts could prolong the survival times for the allogeneic islet grafts and express the hypoimmnoreactivity as demonstrated by the mixed islet-lymphocyte co-cultivation system, thus processing a better immunoisolation effect.