壳寡糖对胰岛β细胞的保护及其体内抗氧化作用的研究

Effect of chitooligosaccharides on protecting pancreatic βcells and its antioxidant ability in vivo

研究了体外研究酶解法制备的壳寡糖（COS）对胰岛β细胞的保护作用,并进一步探讨COS对链脲佐菌素（STZ）诱导的糖尿病（DM）大鼠胰腺的保护及其抗氧化保护机制.通过壳聚糖酶降解壳聚糖制备得到水溶性、低分子量的COS,在细胞水平上,通过形态学观察、四氮唑蓝（MTT）比色法、DNA凝胶电泳、彗星电泳等方法研究不同浓度的COS对链脲佐菌素损伤胰岛β细胞的保护和抑制细胞凋亡的作用;进行了体内实验,通过一般状态观察和病理组织学检查研究了COS对链脲佐菌素诱导的DM大鼠的胰腺保护作用,并对血清中谷胱甘肽过氧化物酶（GSH-PX）、超氧化物歧化酶（SOD）、丙二醛（MDA）浓度、总抗氧化能力（T-AOC）进行了测定.结果表明,COS可以抑制链脲佐菌素诱导的胰岛β细胞凋亡,对受损的胰岛β细胞有显著的保护作用;COS各剂量组对DM大鼠总抗氧化能力和SOD活力均有显著改善,MDA浓度与STZ损伤组比较均有极显著差异;胰腺组织学检查表明COS能减轻胰岛萎缩、数量减少、胰岛细胞丢失、核固缩等胰岛细胞退行性改变症状.

This paper aimed to detect the effect of chitooligosaccharides （COS） prepared by enzymatic hydrolysis on pancreatic cells and further on protecting pancreatic islet in diabetic rats induced by streptozotoein （STZ）, and the antioxidant ability of COS in vivo. The water-soluble COS with lower molecular weight was prepared by enzymatic hydrolysis of ehitosan. The protective effect of COS in vitro on the DNA damage of pancreatic β cells induced by STZ was detected by optical microscope, methyl thiazolyl tetrazolium （MTT） colorimetric assay, DNA gel electmphoresis and Comet assay, respectively; The activity of GSH-PX and SOD, capability of T-AOC, content of MDA, tissue slice of pancreas were examined after 60 days feeding to determine the effect of COS on diabetic rats induced by STZ. The experiments indicated that the COS had the prominent protective effect on the pancreatic β cells damaged by STZ, and could prohibit the apoptosis of pancreatic β cells. The COS with different concentration has the effect to improve the capability of T-AOC and activity of SOD, and the content of MDA decreased drastically. Morphological investigation on pancreas showed that COS had positive effect on reduction of islets, loss of pancreastic cells, nuclear pyknosis of pancreastic ceils, etc.