钴原卟啉诱导血红素氧化酶-1表达上调对异种移植胰岛的保护作用

目的 研究不同浓度钴原卟啉(CoPP)与其诱导胰岛细胞血红素氧化酶-1(HO-1)表达的效应关系,探讨HO-1表达上调对异种移植胰岛的保护作用.方法 将分离和纯化的供者胰岛随机分为5组(A、B、C、D和E组),分别置于含有不同摩尔浓度CoPP的培养液中诱导,5组CoPP的浓度依次为0、5、25、50和75 mmol/L.检测各组胰岛细胞中HO-1mRNA和HO-1蛋白表达情况,并测定体外胰岛素释放水平,筛选出能诱导HO-1表达上调幅度最高的CoPP合适浓度.再将受者分为研究组和对照组(每组8只),对照组移植未经CoPP诱导的供者胰岛细胞;研究组移植经合适浓度CoPP诱导的供者胰岛细胞,术后每天监测受者血糖和排斥反应情况.结果 D组HO-1mRNA、蛋白表达上调幅度以及胰岛素分泌量均高于其他4组,差异均有统计学意义(P＜0.05),诱导胰岛细胞HO-1上调幅度最高的CoPP浓度为50 mmol/L.研究组受者移植D组供者胰岛后,维持正常血糖的时间为(14.63±1.19)d,对照组为(9.88±2.17)d,两组比较,差异有统计学意义(P＜0.01).结论 在异种胰岛移植中,经50 mmol/L的CoPP体外诱导供者胰岛HO-1表达上调幅度最高;HO-1的表达上调可以促进移植胰岛的功能恢复,抑制排斥反应,延长移植胰岛的存活时间.

Protective effect of cobalt protoporphyrin-induced the strong expression of heme oxygenase-1 on islet xenotransplant

Objective To analyze the dose-effect relationship between cobalt protoporphyrin (CoPP) and heme oxygenase-1 (HO-1) expression in islets and to investigate the protective effect of strongly expression of HO-1 in islet xenotransplantation. Methods Donor islets isolated and purified from SD rats were randomly divided into 5 groups and incubated with different doses of CoPP for 24 h.Group A: 0 mmol/L; Group B: 5 mmol/L; Group C: 25 mmol/L; Group D: 50 mmol/L; Group E:75 mmol/L. The expression of HO-1 mRNA and protein in islets was detected by RT-PCR and Western blot respectively. Glucose of low and high concentrations was added to islets in vitro to test insulin-releasing function. The optimal dose of CoPP which could induce the strongest HO-1 expression was chosen according to the results. Recipients were randomly divided into 2 groups. Control group received untreated xeno-islets, and the experimental group received islets incubated with optimal CoPP close in vitro. Glycemia and rejection were observed after transplantation daily. Results The expression of HO-1 mRNA and protein in xeno-islets of group D was significantly higher than in other groups (P＜0.05). After stimulation of glucose, the insulin concentration in group D was significantly higher than in other groups (P＜0.05). The optimal dose of CoPP which could induce the strongest HO-1 expression was 50 mmol/L. The time for normoglyeemia in experimental group was (14.63±1.19) days, significantly longer than that in control group (9.88±2.17)days (P＜0.01). Conclusion The strongest expression of HO-1 induced by CoPP in vitro promotes the glucose-stimulated insulin secretion of islets and prolonged the survival of xeno-islet grafts by protecting them from rejection.