地黄多糖对DSS诱导的小鼠溃疡性结肠炎的治疗作用

Therapeutic effect of Rehmannia glutinosa polysaccharide on DSS-induced ulcerative colitis in mice

目的探讨地黄多糖对葡聚糖硫酸钠(DSS)诱导的小鼠溃疡性结肠炎的治疗作用及机制。方法提取生、熟地黄水提物及多糖,并测定生、熟地黄多糖相对分子量及单糖组成。将70只ICR小鼠随机分为空白组、模型组(DSS组)、美沙拉嗪组(5-ASA组)、生地黄水提物组(RR组)、熟地黄水提物组(PR组)、生地黄多糖组(RRP组)、熟地黄多糖组(PRP组),每组10只。第1~7天,除空白组外,其余小鼠饮用3%的DSS;第8~14天,空白组和DSS组小鼠饮用无菌水,5-ASA组、RR组、RRP组、PR组和PRP组分别给予美沙拉嗪、生地黄水提物、生地黄多糖、熟地黄水提物及熟地黄多糖,给药剂量均为200 mg/kg。实验过程中每天记录小鼠的体质量、粪便硬度及直肠出血情况(疾病活动指数);测量小鼠结肠长度;采用HE染色法观察结肠组织病理形态变化;ELISA法测定结肠组织中髓过氧化物酶(MPO)活性及LPS水平。结果生、熟地黄多糖分子量均可分为约200 kD和4 kD。生地黄多糖由葡萄糖、半乳糖、半乳糖醛酸、甘露糖、鼠李糖、木糖、岩藻糖7种单糖所组成,熟地黄多糖由葡萄糖、半乳糖、半乳糖醛酸、甘露糖、木糖、岩藻糖6种单糖组成。与空白组相比,DSS组小鼠体质量明显下降(P<0.0001),DAI评分显著提高(P<0.0001),小鼠结肠长度缩短(P<0.05),脾脏质量增加(P<0.0001),结肠组织中MPO酶活性和血清中LPS含量升高(P<0.05)。与DSS组相比,5-ASA组、RR组、RRP组和PR组疾病活动指数显著下降(P<0.05);PRP组疾病活动指数评分最低(P<0.0001);PR组结肠长度显著增长(P<0.05);5-ASA组、RR组、PR组脾脏指数显著下降(P<0.01);多糖组(RRP和PRP组)下降最多(P<0.001);RR组、RRP组、PR组和PRP组结肠中MPO酶活性显著降低(P<0.05);PR组血清中LPS含量显著降低(P<0.05)。结论生、熟地黄多糖及水提物均能够改善结肠病理组织,且熟地黄水提物及多糖对结肠炎小鼠治疗效果较好。

Objective To investigate the effect and mechanism of raw rehmannia root polysaccharides(RRP),prepared rehmannia root polysaccharides(PRP),raw rehmannia root extract(RR),and prepared rehmannia root extract(PR)on dextran sodium sulfate(DSS)-induced ulcerative colitis(UC)in mice.Methods RR,PR,RRP and PRP were prepared,and the molecular weight and the monosaccharide composition of RRP and PRP were determined.Seventy ICR mice were randomly divided into control group,model group(DSS group),metharazine group(5-ASA group),RR group,PR group,RRP group,and PRP group,with 10 mice in each group.At days 1-7,all the mice drank 3%DSS except the mice in control group.At days 8-14,the mice in control group and DSS group drank sterile water,and the mice in 5-ASA group,RR group,RRP group,PR group and PRP group were given mesalazine,raw rehmannia root extract,raw rehmannia root polysaccharide,prepared rehmannia root extract and prepared rehmannia root polysaccharide at a dose of 200 mg/kg,respectively.During the experiment,the body weight,the fecal hardness and the rectal bleeding(disease activity index,DAI)of mice were recorded daily,and the colon length of mice was measured.HE staining was used to observe the pathological changes of colon tissue.And MPO activity and LPS level in colon tissue were determined by ELISA.Results The molecular weight of RRP and PRP included two kinds of about 200 kD and 4 kD.The polysaccharide of RRP was composed of glucose,galactose,galacturonic acid,mannose,rhamnose,xylose and fucose.And the PRP was composed of glucose,galactose,galacturonic acid,mannose,xylose and fucose.Compared with control group,the body weight was significantly decreased in DSS group(P<0.0001),the DAI score was significantly increased(P<0.0001),the colon length was shortened(P<0.05),the spleen weight was increased(P<0.0001),and the MPO enzyme activity in colon tissue and the serum LPS content in the serum were increased(P<0.05).Compared with DSS group,the DAI score was decreased in 5-ASA group,RR group,RRP group,PR group and PRP group(P<0.05),especially in PRP group(P<0.0001).Compared with DSS group,the colon length was significantly increased in PR group(P<0.05).Compared with DSS group,the spleen index was significantly decreased in 5-ASA group,RR group,PR group,RRP group and PRP group(P<0.01),especially in RRP group and PRP group(P<0.001).Compared with DSS group,the activity of MPO enzyme in colon was significantly decreased in RR group,RRP group,PR group and PRP group(P<0.05),and the content of LPS in serum was significantly decreased in PR group(P<0.05).Conclusion RR,RRP,PR and PRP can improve the pathological tissue of colon,and PRP and PR have a better therapeutic effect on UC in mice.