【摘要】 为了研究绞股蓝多糖(Gynostemma pentaphyllum polysaccharides, GPP)对热应激小鼠小肠形态结构和紧密连接闭锁小带蛋白-1(zonula occludens, ZO-1)、闭合蛋白(occludin, OCLN)和密封蛋白-1(claudin-1,CLDN-1)表达的影响，试验将50只SPF级昆明小鼠随机分为空白对照组、热应激组及低剂量GPP(50 mg/kg)组、中剂量GPP(100 mg/kg)组、高剂量GPP(200 mg/kg)组，采用苏木精-伊红(H.E.)染色观察各组小鼠十二指肠、空肠和回肠的形态结构，测量绒毛高度(VH)和隐窝深度(CD)及其比值(VH/CD,V/C),统计杯状细胞(GC)和肠上皮柱状细胞间淋巴细胞(IEL)数量并分析；采用免疫组织化学技术分别测定并分析各组小鼠十二指肠、空肠和回肠紧密连接蛋白ZO-1、OCLN和CLDN-1的表达量。结果表明：与中剂量GPP组相比，低剂量GPP组小肠各段肠绒毛排列规则、断裂情况改善、间隙紧凑，肠绒毛顶端上皮细胞脱落较少。低剂量GPP组小肠各段VH、十二指肠和空肠V/C比值均显著高于热应激组(P<0.05),十二指肠CD显著低于热应激组(P<0.05);低剂量GPP组和中剂量GPP组小鼠小肠各段GC数量均显著高于热应激组(P<0.05);低剂量GPP组和中剂量GPP组小鼠小肠各段IEL数量均显著低于热应激组(P<0.05)。不同剂量的GPP均可增加热应激小鼠小肠各段紧密连接蛋白ZO-1、OCLN和CLDN-1表达量，其中与热应激组相比，低剂量GPP组小肠各段紧密连接蛋白ZO-1、OCLN和CLDN-1表达量均显著增加(P<0.05);中剂量GPP组十二指肠和回肠紧密连接蛋白ZO-1表达量均显著增加(P<0.05),空肠和回肠紧密连接蛋白OCLN表达量均显著增加(P<0.05),小肠各段紧密连接蛋白CLDN-1表达量显著增加(P<0.05);高剂量GPP组回肠紧密连接蛋白ZO-1表达量显著增加(P<0.05)。说明GPP可改善热应激条件下小鼠小肠各段形态结构及提高紧密连接蛋白ZO-1、OCLN和CLDN-1表达量，保护热应激小鼠肠上皮细胞之间的紧密连接，增加肠屏障的完整性，从而维持肠道正常功能，其中低剂量GPP(50 mg/kg)改善效果较为明显。更多还原

【Abstract】 In order to investigate the effects of Gynostemma pentaphyllum polysaccharides(GPP) on the morphological structure of the small intestine and the expression of tightly junction(TJ) zonula occludens-1(ZO-1), occludin(OCLN) and claudin-1(CLDN-1) in heat-stressed mice, 50 SPF-grade Kunming mice were randomly divided into five groups: the blank control group, the heat stress group, the low-dose GPP(50 mg/kg) group, the medium-dose GPP(100 mg/kg) group, and the high-dose GPP(200 mg/kg) group. Hematoxylin-eosin(H.E.) staining was used to observe the morphological structure of duodenum, jejunum and ileum of the mice in each group; the villus height(VH) and crypt depth(CD) and VH/CD(V/C) ratios were determined, and the goblet cell(GC) and intestinal epithelial columnar intercellular lymphocyte(IEL) counts were counted and analyzed. Immunohistochemistry was used to determine and analyze the expression levels of ZO-1, OCLN and CLDN-1 of TJ proteins in duodenum, jejunum and ileum. The results showed that compared with the medium-dose GPP group, the intestinal villi in all segments of the small intestine were arranged regularly in the low-dose GPP group; the breakage was improved, the gaps were compact, and the shedding of epithelial cells at the top of the intestinal villi was less. VH in all segments of the small intestine, as well as the V/C ratio in the duodenum and jejunum of the low-dose GPP group were significantly higher than those of the heat stress group(P<0.05), while the CD in the duodenum was significantly lower than that of the heat stress group(P<0.05). The number of GC in all segments of the small intestine of mice in both the low-dose GPP group and the medium-dose GPP group was significantly higher than that in the heat stress group(P<0.05). The IEL in all segments of the small intestine of mice in both the low-dose GPP group and the medium-dose GPP group was significantly lower than that in the heat stress group(P<0.05). Different doses of GPP could increase the expression levels of tight junction proteins ZO-1, OCLN, and CLDN-1 in various segments of the small intestine in heat-stressed mice. Compared with the HS group, the low-dose GPP group showed a significant increase in the expression levels of tight junction proteins ZO-1, OCLN, and CLDN-1 in all segments of the small intestine(P<0.05); the medium-dose GPP group exhibited a significant increase in the expression levels of tight junction protein ZO-1 in the duodenum and ileum(P<0.05), a significant increase in the expression levels of tight junction protein OCLN in the jejunum and ileum(P<0.05), and a significant increase in the expression levels of tight junction protein CLDN-1 in all segments of the small intestine(P<0.05); the high-dose GPP group displayed a significant increase in the expression levels of tight junction protein ZO-1 in the ileum(P<0.05). The results indicate that GPP could improve the morphological structure of each segment of the small intestine in mice under HS conditions, increase the expression levels of tight junction proteins ZO-1, OCLN, and CLDN-1, protect the tight junctions between intestinal epithelial cells in HS mice, enhance the integrity of the intestinal barrier, thereby maintaining the normal function of the intestine. Among them, the low-dose GPP(50 mg/kg) have a more obvious improvement effect.更多还原