海地瓜岩藻聚糖硫酸酯对环磷酰胺损伤小鼠小肠粘膜的保护作用

Protective effects of Acaudina molpadioides fucoidan on small intestinal mucosa injury induced by cyclophosphamide in mice

目的探讨海地瓜岩藻聚糖硫酸酯,包括原糖及其不同分子量酶解产物(50、100、500kD)对环磷酰胺造成的小鼠小肠粘膜损伤的改善作用,幵对其机制进行探究。方法 60只Balb/c小鼠随机分成6组:空白对照组,环磷酰胺模型组,环磷酰胺损伤小鼠分别干预原糖及50、100、500kD酶解产物组,每组10只。实验周期为14 d,干预组分别ig给予50 mg/(kg·bw)海地瓜岩藻聚糖硫酸酯,第12和13 d给除空白对照组以外小鼠连续ip给予50 mg/(kg·bw)环磷酰胺。测定小鼠体重变化,器官指数变化;采用苏木精-伊红染色法检测小肠组织形态学变化;采用实时荧光定量PCR技术检测溶菌酶、黏蛋白(mucin2,Muc2)、干细胞标志物(leucine-rich repeat-containing G-protein coupled receptor5,Lgr5)mRNA表达水平,幵通过Toll样受体(toll-like receptors, TLRs)和髓样分化因子(myeloid differentiation factor88, MyD88)基因表达的变化探究其作用机制。结果 100 kD和50 kD组枀显著(P<0.01)改善环磷酰胺造成的小鼠体重下降; 50 kD组显著(P<0.05)提高绒毛长度和隐窝深度比值,改善小鼠小肠形态破坏; 100 kD组和50 kD组小肠溶菌酶、Muc2基因表达量显著高于Cy组,不同分子量的酶解产物均能显著提高Lgr5以及小肠TLRs (TLR-4, TLR-5, TLR-9)和MyD88的基因表达量,且50kD组的改善作用最好。结论酶解片段对化疗型小鼠小肠粘膜损伤的保护效果优于原糖,且50 kD效果最好,作用机制可能与对TLRs/MyD88信号通路的调节有关。

Objective To investigate the ameliorative effects of a kind of sea cucumber fucoidan(SC-FUC)from Acaudina molpadioides,including fucoidan and its different molecular weight digestion fragments(50,100,500 kD)on small intestinal mucosa injury induced by cyclophosphamide in mice,and to explore its mechanism.Methods A total of 60 Balb/c mice were randomly divided into 6 groups:normal group,cyclophosphamide group(Cy),cyclophosphamide-injured mice intervened by Acaudina molpadioides fucoidan group(Fuc),by 500 kD Acaudina molpadioides fucoidan(500 kD),by 100 kD Acaudina molpadioides fucoidan(100 kD),and by 50 kD Acaudina molpadioides fucoidan group(50 kD),with 10 mice in each group.The experimental period was 14 days.The intervention group was intragastrically administered 50 mg/(kg·bw)SC-FUC,and mice other than the control group were given continuous intraperitoneal injection of 50 mg/(kg·bw)cyclophosphamide on the 12 th and 13 th days.The changes of body weight,organ indexes during the experiment period were measured.Morphological changes of small intestine were observed by haematoxylin and eosin staining.Real-time fluorescence quantitative PCR technology was used to analyze the mRNA expression levels of lysozyme,mucin2 and stem cell marker Lgr5,and the improvement effect of SC-FUC on intestinal mucosal injury caused was explore by cyclophosphamide in mice.The mechanism was studied by the changes of the expression of toll-like receptors(TLRs)and myeloid differentiation factor88(MyD88)genes.Results The 100 kD and 50 kD Acaudina molpadioides fucoidan digested fragments could significantly relieve the loss of body weight induced by chemotherapy(P<0.01).In the 50 kD group,the ratio of villus length to crypt depth was significantly increased(P<0.05),and the morphological damage of small intestine was improved.The expression of lysozyme and mucin2 in the small intestine of 100 kD and 50 kD groups were significantly higher than that of the Cy group.The digestion fragments of Fuc with different molecular weights could significantly increase the expression of Lgr5.The mRNA expression of TLRs(TLR-4,TLR-5,TLR-9)and MyD88 in the small intestine were significantly up-regulated by digestion fragments,and the 50 kD fragment had the best effect.Conclusion The protective effect of the digestion fragments on the small intestinal mucosa injury is better than that of the Fuc,and the 50 kD fragment has the best effect.The mechanism is probably related to the TLRs/MyD88 signaling pathway.