白芨多糖对葡聚糖硫酸钠诱导的小鼠溃疡性结肠炎治疗模型的优化和建立

Optimization and establishment of therapeutic model of Bletilla striata polysaccharide on dextran sodium sulfate-induced ulcerative colitis in mice

目的建立白芨多糖(Bletilla striata polysaccharide,BSP)对葡聚糖硫酸钠(dextran sodium sulfate,DSS)诱导的小鼠溃疡性结肠炎(ulcerative colitis,UC)的最优化治疗模型。方法将48只雄性C57BL/6小鼠随机分为正常对照组、DSS模型组(25 g/L DSS)及BSP低、中、高剂量组(25 g/L DSS分别联用95、190、380 mg/kg BSP)和柳氮磺胺吡啶(salazosulfapyridine,SASP)(25 g/L DSS+320 mg/kg SASP为阳性对照)组,正常对照组自由饮用蒸馏水,其余各组均给予25 g/L的DSS溶液自由饮用7 d;BSP低、中、高剂量组和SASP(阳性对照)组第2天起根据体质量分别按分组进行灌胃给药,正常对照组和DSS模型组灌胃等量生理盐水,每天1次,连续7 d。每天记录小鼠的精神状态、体质量、大便性状和血便情况,计算小鼠疾病活动指数(disease activity index,DAI)。于第9天处死小鼠,取结肠组织,进行苏木精-伊红(HE)染色和组织病理学评分,并用Western blotting检测结肠组织紧密连接蛋白(Claudin-1)的表达。结果与正常对照组相比,DSS模型组小鼠有明显的UC临床表现和组织病理学改变,体质量减轻,组织病理学评分和DAI评分升高(P<0.05),结肠组织Claudin-1蛋白表达减少(P<0.05);与DSS模型组相比,BSP低、中、高剂量组UC临床表现和结肠黏膜损伤均得到不同程度的改善,其中又以BSP高剂量(380 mg/kg)组作用效果为最佳;该组体质量减轻程度、组织病理学评分及DAI评分均明显低于DSS模型组(P<0.05),同时Claudin-1表达明显增加(P<0.05)。结论380 mg/kg BSP灌胃时,对25 g/L DSS诱导的UC小鼠治疗效果最佳,此模型可作为有效模型用于白芨多糖对UC小鼠的进一步研究。

Objective To establish the optimal treatment model of Bletilla striata polysaccharide(BSP)on dextran sodium sulfate(DSS)-induced ulcerative colitis(UC)in mice.Methods We randomly divided 48 male C57BL/6 mice into normal control group,DSS model group(25 g/L DSS),BSP low-,medium-and high-dose groups(25 g/L DSS+95,190,380 mg/kg BSP),and salazosulfapyridine(SASP)(25 g/L DSS+320 mg/kg SASP,positive control)group.Mice in the normal control group drank distilled water freely,while the other groups were given 25 g/L DSS solution to drink freely for 7 days.From the second day,the low-,medium-and high-dose BSP groups and SASP(positive control)group were administered by gavage according to body mass.The normal control group and DSS model group were given the same amount of normal saline once a day for 7 consecutive days.The mice’s blood pressure was recorded every day.Mental state,body mass,stool characteristics and bloody stool were used to calculate the mice’s disease activity index(DAI).The mice were killed on the 9th day,and their colonic tissues were taken for hematoxylin eosin(HE)staining and histopathological scoring.The expression of tight junction protein Claudin-1 in colonic tissues was detected by Western blotting.Results Compared with the normal control group,the DSS model group had obvious clinical manifestations,histopathological changes and reduced body weight,increased histopathological score and DAI score(P<0.05),and decreased expression of tight junction protein Claudin-1 in colon tissue(P<0.05).Compared with those in DSS model group,the clinical manifestations of UC and colonic mucosal injury in low-,medium-and high-dose BSP groups were improved in varying degrees.The high-dose(380 mg/kg)BSP group had the best effect.The degree of body weight reduction,histopathological score and DAI score in this group were significantly lower than those in DSS model group(P<0.05),whereas the expression of Claudin-1 increased significantly(P<0.05).Conclusion When BSP was administered by gavage at 380 mg/kg,the therapeutic effect on UC mice induced by 25 g/L DSS was the best.This model can be used as an effective one for further studies on Striata Bletilla polysaccharide in UC mice.