不同分子量壳寡糖对促胰岛细胞增殖、胰岛素分泌及调节餐后血糖的作用

Antidiabetic effects of chitooligosaccharides with different molecular weights on pancreatic islet cells in streptozotocin-induced diabetic rats

目的:研究酶解法制备的不同分子量壳寡糖对胰岛β细胞系NIT-1的促增殖及胰岛素分泌作用,并进一步探讨在体内壳寡糖降低链脲佐菌素诱导的糖尿病大鼠的餐后2h血糖的作用.方法:通过壳聚糖酶降解壳聚糖制备得到水溶性的不同分子量的壳寡糖,在细胞水平上,通过形态学观察、MTT比色法、放射免疫等方法研究不同分子量的壳寡糖对于胰岛β细胞系NIT-1细胞的增殖及促胰岛素分泌作用;体内实验,通过一般状态观察、餐后2h血糖、尿糖、糖耐量测定研究了不同分子量壳寡糖对链脲佐菌素诱导的糖尿病大鼠降低餐后2h血糖和改善葡萄糖耐量的作用.结果:不同分子量壳寡糖对于胰岛β细胞体外增殖具有明显的促进作用并可以显著促进胰岛β细胞的胰岛素分泌,低分子量壳寡糖在体内能有效改善糖尿病大鼠的体重减轻、多饮、多食等症状,降低餐后2h血糖值(22.13±3.23,21.78±3.09,21.32±3.02,19.73±4.12,17.88±3.14,16.14±3.55vs39.38±3.08,均P<0.01),改善葡萄糖耐量(101.19±12.44,99.61±13.11,96.79±9.22,94.79±13.20,89.41±11.10,84.08±5.93vs122.40±12.05,P<0.05或0.01).各组培养2-14d的胰岛细胞的生物学活性活跃,对葡萄糖刺激具有良好反应,其中MⅥ组的胰岛素刺激指数与对照组比较有显著差异(2.94vs2.01,P<0.05).结论:壳寡糖具有多种生物活性,可以应用于糖尿病的治疗,低分子量壳寡糖有较好的降血糖效果.

AIM： To estimate effects of varying molecular chitooligosaccharides prepared by enzymatic hydrolysis on the proliferation of pancreatic islet cells, and to investigate the release of insulin and 2 h plasma glucose in streptozotocin-induced diabetic rats. METHODS： Chitooligosaccharides were prepared by enzymatic hydrolysis. The effects of varying molecular chitooligosaccharides on pro-liferation of pancreatic islet cells and the release of insulin in vitro were detected using optical microscopy, MTT colorimetric assay and radioimmunoassay methods respectively; the general clinical symptoms, 2 h plasma glucose and oral glucose tolerance were examined to determine the effects of chitooligosaccharides on diabetic rats induced by streptozotocin. RESULTS： The results indicated that chitooligosaccharides markedly accelerated the proliferation of the pancreastic B cells. Chitooligosaccharides had prominent effects on insulin release. Lower molecular chitooligosaccharides improved general clinical symptoms of DM rats, decreased the 2 h plasma glucose levels （22.13 ± 3.23, 21.78 ± 3.09, 21.32 ± 3.02, 19.73 ± 4.12, 17.88 ± 3.14, 16,14 ± 3.55 vs 39.38 ± 3.08, all P 〈 0.01） and improved glucose tolerance （101.19 ± 12.44, 99.61 ± 13.11, 96.79 ± 9.22, 94.79 ± 13.20, 89.41 ± 11.10, 84.08 ± 5.93 vs 122.40 ± 12.05, P 〈 0.05 or 0.01）. 2-14 d culture of each group of islet cell biology activity was active with good response to glucose stimulation. In MⅥ group, significant difference was observed in insulin stimulation index compared with the control group （2.94 vs 2.01, P 〈 0.05）. CONCLUSION： Chitooligosaccharides possess various biological activities and can be used in the treatment of diabetes mellitus. The lower molecular chitooligosaccharide has better effect.