岩藻多糖对高尿酸血症小鼠肠粘膜屏障功能保护作用

Fucoidan protects intestinal mucosal barrier function in hyperuricemic mice

目的探讨岩藻多糖对高尿酸血症模型小鼠肠黏膜屏障功能的保护作用及机制。方法采用40只C57BL/6J小鼠建立高尿酸血症模型,随机分为4组,分别为对照组、高尿酸血症模型组、岩藻多糖干预组、别嘌呤醇阳性对照组,每组10只。比色法测定小鼠血清尿酸(UA)水平,ELISA法检测脂多糖(LPS)、二胺氧化酶(DAO)以及肿瘤坏死因子(TNF-α)、白介素-1β(IL-1β)水平。小鼠回肠组织病理变化采用苏木精–伊红(HE)染色法进行观察,生物素示踪实验观察回肠组织通透性,蛋白印迹法测定小肠组织中紧密连接蛋白、自噬相关蛋白等的表达。结果与模型组比较,岩藻多糖使高尿酸血症模型小鼠的血清尿酸水平明显下降52.45%、TNF-α水平明显下降29.18%、IL-1β水平明显下降25.36%;与对照组比较,LPS水平明显降低27.24%、DAO水平明显降低21.78%(P<0.05),改善肠黏膜细胞通透性,增加ZO-l、occludin的表达水平(P<0.05)。与模型组相比,岩藻多糖组LC3BⅡ/Ⅰ比值及beclin-1蛋白表达水平明显升高(P<0.05);p38 MAPK表达水平明显增加(P<0.05),p-mTOR表达水平明显降低(P<0.01)。结论岩藻多糖降低高尿酸血症小鼠血清尿酸水平,并通过上调p38 MAPK/mTOR通路增强小肠黏膜细胞自噬水平,减轻肠黏膜屏障损伤。

Objective To investigate the protective effect and mechanism of fucoidan on intestinal mucosal barrier function in hyperuricemic mice.Methods Forty specific pathogen-free(SPF)C57BL/6J mice were randomly assigned into a control,hyperuricemia model,fucoidan treatment(by gavage administration at the dosage of 200 mg/kg/day continuously for 10 weeks),and allopurinol positive control group(10 in each group).By the end of the treatments for the mice of the four groups,serum uric acid(UA)was measured with colorimetric method;serum lipopolysaccharides(LPS),diamine oxidase(DAO),tumor necrosis factor(TNF-α)and interleukin-1β(IL-1β)were measured with enzymelinked immunosorbent assay(ELISA).Histopathological changes in ileum mucosa were observed with hematoxylin-eosin(HE)staining;the expressions of tight junction proteins in ileum mucosa and autophagy-related proteins in small intestine were determined with Western blot.Results Significant decreases in serum UA(52.45%),TNF-α(29.18%),IL-1β(25.36%),LPS(27.24%),and DAO(21.78%)were detected in the hyperuricemic mice with fucoidan treatment(P<0.05 for all);in addition,the fucoidan-treated hyperuricemic mice had significantly improved intestinal cell junctions and permeability,increased expressions of zonula occludens-1(ZO-l),occludin and autophagy-related proteins(all P<0.05).Compared to those in model mice,significantly increased ratio of autophagy-related proteins light chain 3B II/I(LC3BII/I),beclin-1,and phosphorylated p38 mitogen-activated protein kinase(p-p38 MAPK)but significantly decreased phosphorylated mammalian target of rapamycin(p-mTOR)were observed in the hyperuricemic mice with fucoidan treatment.Conclusion Oral administration of fucoidan could effectively reduce serum uric acid and improve intestinal mucosal barrier damage by increasing autophagy via p38 MAPK/mTOR pathway in hyperuricemic mice.