白簕多糖对1型糖尿病小鼠短链脂肪酸、炎症因子及紧密连接蛋白的影响

Effect of Acanthopanax trifoliatus Polysaccharide on SCFAs,Inflammatory Factors and Tight Junction Protein in Diabetic Mice

目的 通过考察短链脂肪酸(SCFAs)及肠道结构变化等因素,探讨白簕精制多糖(ATP1-1)降低链脲佐菌素(STZ)所致1型糖尿病小鼠血糖的机制。方法 连续5天腹腔注射STZ建立糖尿病小鼠模型,随机分为模型组、二甲双胍组(185 mg/(kg·d),ig),ATP1-1高、中、低剂量组(140、70、35 mg/(kg·d),ig),另设正常组,各组小鼠给药治疗6周,于给药期间测定小鼠体重、饮食饮水、血糖等指标,实验结束前测定糖耐量;小鼠处死后,HE染色观察结肠组织病理状况,通过顶空气相法测定各小鼠粪便SCFAs水平,并采用实时荧光定量PCR法考察肠道Claudin-1、TNF-α、IL-6及IL-10 mRNA的表达。结果 连续6周给药ATP1-1可改善糖尿病小鼠的“三多一少”症状,与模型组相比,ATP1-1各剂量组小鼠空腹血糖及糖耐量AUC水平均显著降低(P<0.05),血糖恢复时间明显缩短;中、高剂量组的丙酸、异丁酸、异戊酸和戊酸的含量均显著高于模型组,且趋近正常组,部分甚至高于正常组。ATP1-1各剂量给药均可显著逆转Claudin-1 mRNA的下调(P<0.01),并呈剂量依赖性;同时,ATP1-1还可降低肠道TNF-α、IL-6促炎因子表达,提高抗炎因子IL-10的表达。结论 ATP1-1可通过增加SCFAs分泌量,从而改善肠道黏膜屏障、减轻肠道炎症反应,最终降低糖尿病小鼠血糖。

OBJECTIVE To study the mechanism of hypoglycemic effect of neutral polysaccharide from Acanthopanax trifoliatus(L.) Merr.(ATP1-1) on STZ-induced diabetic mice,contents of short chain fatty acids(SCFAs) and intestinal changes were investigated.METHODS Mice were received intraperitoneal injection with STZ for 5 consecutive days to induce diabetes,then randomly divided into five groups:diabetic group,metformin group(185 mg/(kg·d),ig),low-(35 mg/(kg·d),ig),mid-(70 mg/(kg·d),ig),and high-dose(140 mg/(kg·d),ig) ATP1-1 groups,and normal groups.Body weight,water,food intake and blood glucose were measured during the 6-week intragastrical administration,and oral glucose tolerance were detected at the end of the experiment.After mice were sacrificed,histopathological changes of colon tissues were observed by HE staining,contents of SCFAs in feces were detected by HS-GC,and the expression of Claudin-1,TNF-α,IL-6,IL-10 mRNA in intestine were detected by qPCR.RESULTS After continuous administration of ATP1-1 for 6 weeks,the blood glucose and AUC of OGTT reduced obviously in mice of mid-and high-dose group(P<0.05),and the recovery time in OGTT were also shorter than that of diabetic group.Contents of propionic acid,isobutyric acid,isovaleric acid and valeric acid in the mid-and high-dose group were significantly higher than diabetic group,and showed no significant difference with that in normal group.All doses of ATP1-1 reversed the down-regulation of the expression levels of Claudin-1 mRNA in a concentration-dependent manner(P<0.01).Meanwhile,ATP1-1 decreased the expression of colon pro-inflammatory factors TNF-α and IL-6 and increased the anti-inflammatory factors IL-10.CONCLUSION The mechanism of hypoglycemic effect of ATP1-1 on diabetic mice can be related to increasing the secretion of SCFAs,thus restoring intestinal mucosal barrier and alleviating intestinal inflammation.