复合膳食纤维对大鼠肠道形态结构及功能的长期影响

Effect of chronic intake of dietary fiber complex on the intestinal structure and function in hypercholesterolemic rats

为观察长期进食复合膳食纤维 (DFC)对高脂血症大鼠肠道形态结构及功能的影响。选健康、断乳SD大鼠 60只 ,雌雄各半 ,经高脂饲料诱导形成高脂血症模型后 ,按体重及血胆固醇水平均衡的原则分为 5组 ,分别以基础饲料及小麦纤维作为对照组 (A、B)其余 3组给不同剂量的DFC(C～E组 ,总膳食纤维含量分别为 4 %、1 6 %、64 % ) ,实验期为三月 ,通过测量分析及光镜、电镜形态观察的方法 ,研究DFC对大鼠肠道结构与功能的影响。结果显示 ,1 DFC含量较高剂量的D、E两组动物粪重显著增加 ,小肠壁重量显著高于正常及高脂对照组 ,E组动物盲肠壁重量显著高于正常及高脂对照组 (P <0 0 5) ;2 不同水平DFC组大鼠小肠绒毛变短、变宽 ,粘膜肌层增厚 ,最高剂量的E组动物小肠绒毛出现水肿 ;各水平DFC组动物直肠光镜下无明显形态学改变 ;3 各水平DFC组大鼠小肠微绒毛不同程度变短 ,排列紊乱 ,局部缺失 ,细胞器肿胀 ,以线粒体病变最为明显 :基质肿胀、嵴断裂、有的消失 ,重出现空泡变 ;4 直肠微绒毛改变不明显 ,线粒体改变同小肠。结论长期摄入高剂量DFC在增加粪便量排出的同时会影响大鼠肠道的形态结构 ,可能会对肠道的某些功能产生不利影响 。

To investigate the long term effect of dietary fiber complex (DFC) on intestinal structure and function in hypercholesterolemic rats, 60 healthy SD rats were feed with food rich in lipids and hypercholesterolemic animal models were established. The animals were randomly divided into 5 groups. Rats were fed DFC at levels of 4%, 16%, or 64% for three month in the experimental groups. Wheat fiber was used in the hypercholesterolemic control (HC) group and rats feeding on normal food were used as normal control (NC). Morphology of the small intestine,reticum and caecum were observed by light and electron microscope examination. Intestinal function was measured physically.The results showed that (1) compared with NC group, fecal weight was significantly raised in DFC group of higher level (group D and E, P <0 05);(2) the weights of small intestine wall in D and E group were significantly higher than those of NC and HC group and weights of caecum wall in E group were significantly higher than those of NC and HC group ( P <0 05);(3) widen villi and thickened muscle layer of small intestine were observed in DFC group of higher level. No demonstrable changes in reticulum morphology in any group of animals were found under the observation of light microscope (4) microvilla becoming short and/or absent, mitochondria swelling, impairment of the integrity of the cristae were commonly observed in DFC groups. Conclusions Long term intake of DFC composed mainly of Hippophae rhamnoides L,Bran, oat bran and guar gum at higher levels might induce some morphological changes of intestine and caecum. Therefore, DFC might be used at low level as an effective cholesterol lowering agent.