壳寡糖及其衍生物对实验性糖尿病大鼠抗氧化能力及肾功能的影响

Effects of chitooligosaccharides and its derivatives on antioxygenization and renal function in experimental diabetes rats

背景:壳寡糖和N-乙酰氨基单糖是高分子不溶性壳聚糖经水解的产物,具有水溶性。由于分子结构相似,壳寡糖和N-乙酰氨基单糖壳聚糖同样具有抗氧化等功效,同时由于其小分子可溶性和易被人体吸收的特性,在糖尿病及其并发症预防与治疗方面有更广阔的应用前景。目的:观察不同剂量的壳寡糖,N-乙酰氨基单糖对链脲佐菌素诱导的糖尿病大鼠抗氧化能力的影响及对肾脏的保护作用。设计、时间及地点:随机对照动物实验,于2008-07/09在中国海洋大学生物化学实验室完成。材料:壳寡糖,N-乙酰氨基单糖由中国海洋大学生物化学实验室制备。81只Wistar大鼠随机分为9组:正常对照组,阴性对照组,二甲双胍组,壳寡糖和N-乙酰氨基单糖低、中、高剂量组,每组9只。方法:正常对照组腹腔内注射柠檬酸缓冲液,其余各组按65mg/kg体质量一次性腹腔内注射链脲佐菌素溶液制备糖尿病大鼠模型。壳寡糖和N-乙酰氨基单糖低、中、高剂量组分别按每日250,500,1500mg/kg灌胃壳寡糖和N-乙酰氨基单糖水溶液,正常对照组,阴性对照组按体质量灌胃等体积凉白开水(10mL/kg),二甲双胍组按每日200mg/kg灌胃二甲双胍水溶液,连续60d。主要观察指标:①测定血清中谷胱甘肽过氧化物酶、超氧化物歧化酶、丙二醛浓度、总抗氧化能力和肾功能指标。②肾脏病理组织学检查。结果:壳寡糖,N-乙酰氨基单糖可以增加糖尿病大鼠血清中总抗氧化能力及超氧化物歧化酶浓度,显著降低血清中丙二醛、尿素氮、N-乙酰氨基葡萄糖苷酶及尿液中总蛋白/肌酐、N-乙酰氨基葡萄糖苷酶/肌酐的水平。其中以壳寡糖中剂量组(500mg/kg)和N-乙酰氨基单糖低剂量组(250mg/kg)作用效果较好。结论:适量壳寡糖及N-乙酰氨基单糖能够有效的降低链脲佐菌素诱导的糖尿病大鼠的抗氧化能力,从而对肾脏起到了保护作用。

BACKGROUND： Chitooligosaccharides and N-acetylglucosamine are products of high polymer insoluble chitosan via hydrolysis, with the water-solubility. Because of similar molecular structure, chitooligosaccharides and N-acetylglucosamine have anti-oxygenization ability, and can be widely used in prevention and treatment of diabetes and its complications, due to the dissolubility and easy absorption. OBJECTIVE： To observe the effect of different doses of chitooligosaccharides and N-acetylglucosamine on improving antioxidant ability and protecting kidney ability in diabetic mouse induced by streptozotocin. DESIGN, TIME AND SETTING： The randomized controlled animal study was performed at the Biochemistry Laboratory of Ocean University of China from July to September 2008. MATERIALS： Chitooligosaccharides and N-acetylglucosamine were prepared at the Biochemistry Laboratory of Ocean University of China. A total of 81 Wistar rats were randomly and equally assigned into normal control group, negative control group, metformin group, low, moderate and high doses of chitooligosaccharides groups, and low, moderate and high doses of N-acetylglucosamine groups. METHODS： Rats in the normal control group intraperitoneally underwent citrate buffer solution. Rats in the other groups were intraperitoneally treated with streptozotocin solution （65 mg/kg） to establish rat diabetes models. Rats in the low, moderate and high doses of chitooligosaccharides groups, and low, moderate and high doses of N-acetylglucosamine groups were separately subjected to chitooligosaccharides and N-acetylglucosamine （daily 250, 500, 1 500 mg/kg） by gavage. Rats in the normal control and negative control groups underwent the same volume of cold water （10 mL/kg）. Rats in the metformin group underwent metformin water solution （200 mg/kg daily） by gavage for successively 60 days. MAIN OUTCOME MEASURES： The following parameters were measured： activities of serum glutathione peroxidase, superoxide dismutase （SOD）, malondialdehyde concentration, total antioxidative capacity （T-AOC）, index about the kidney function and histopathological examination of the kidney. RESULTS： Chitooligosaccharides and N-acetylglucosamine could improve T-AOC and SOD activity, significantly decrease serum malondialdehyde, urea nitrogen, n-acetyl- β-d-glucosaminidase content, and total protein/creatinine, n-acetyl-β-d-glucosaminidase/creatinine levels in urine. The moderate dose of chitooligosaccharide （500 mg/kg） and low dose of N-acetylglucosamine （250 mg/kg） had the better effects. CONCLUSION： Chitooligosaccharides and N-acetylglucosamine can effectively decrease antioxidant capacity in streptozotocin-induced diabetes rats, and finally result in protection on the kidney.