The Influences On The Ultrastructure And Absorption Function Of Colon Mucosa After Total Small Bowel Resection

Objective:To study the influences on the ultrastructure and absorption function of colon mucosa after total Small bowel resectionMethods:SD rats(30) were randomly divided into three groups,Ultra-short bowel group(10 rats):made to ultra-short intestine rats group of 90-95%of intestine resected; sham group(10 rats):given the small intestine after transection again anastomosis; control(10 rats):group with operation not given.Ultra-short intestine rats group and the sham group was given Peptisorb(Pepti-2000) to enteral nutrition(EN) support, control rats used the same method of feeding and nutrition,after 21 days feeding, observed the morphology of colon under optical microscope(colon wall thickness, mucosal thickness,plica height,plica surface area),scanning electron microscopy to observe the morphology of mucosal surface,transmission electron microscopy to observe the ultrastructural changes of intestinal epithelial cells guitar.And to determine the absorption of colon to water,carbohydrates,amino acid,with D-xylose solution and ¹⁵N-glycine on the continuous cycle of colon conducted closed perfusion of the colon for 3 hours.Results:1.Water absorption:The absorption of colon to water significantly enhanced after 3 hours of closed infusion cycle of ultra-short intestine rats group,comparing with the control group(2.61±0.19ml vs 1.26±0.17ml),show statistically significant differences(P＜0.01),There was no differences between sham and control groups, (1.36±0.23ml ml vs 1.26±0.17ml,P＞0.05). 2.D-xylose absorption:The absorption rate of colon to D-xylose in the 1^st and 2^nd hour relatively increased after 3 hours of closed infusion cycle of ultra-short intestine rats group,comparing with the control group(8.04±0.45%vs 5.95±0.34%,12.36±0.43%vs 8.07±0.09%,18.81±0.86%vs 9.48±0.22%) there was statistically significant differences(P＜0.05).There was no differences between sham and control groups(6.10±0.23%vs 5.95±0.34%,8.11±0.15%vs 8.07±0.09%,9.71±0.15% vs 9.48±0.22%,P＞0.05).3.¹⁵N-glycine absorption:The ¹⁵N-glycine absorption rate of colon significantly enhanced after 3 hours of closed infusion cycle of ultra-short intestine rats group,and there were statistically significant differences comparing with control group(0.86±0.26%vs 0.11±0.05%,2.56±0.59%vs 0.464±0.11%,6.35±0.59%vs 1.05±0.46%, P＜0.01).There was no differences between sham and control groups,(0.14±0.06%vs 0.11±0.05%,0.44±0.09%vs 0.46±0.11%,1.26±0.28%vs 1.05±0.46%,P＞0.05).4.Ultra-short intestinal rats after 21 days of the colon,comparing with the sham and control groups,in the rat colon compensatory proliferation morphology had changed significantly.â‘ The colonic wall thickness obviously increased in ultra-short intestine rats group comparing with the control group,(680±10μm vs 639±91μm, P＜0.01).There was no statistically differences between sham and control groups(640±13μm vs639±9μm,P＞0.05).â‘¡The colonic mucosa thickness increased in ultra-short intestine rats group comparing with the control group,(384±15μm vs 344±11μm,P＜0.01).There was no statistically differences between sham and control groups(343±12μm vs 344±11μm,P＞0.05).â‘¢The height of colon plica markedly improved in ultra-short intestine rats group comparing with the control group(287±10μm vs 253±7μm,P＜0.01).No statistically differences in comparison between sham and control groups(258±16μm vs 253±7μm,P＞0.05).â‘£The colon plica surface area markedly increased in ultra-short intestine rats group comparing with the control group(14194±894μm² vs 11089±271μm²,P＜0.01).However,there was no significant differences between sham group and control group(11518±659μm² vs 11089±271μm²,P＞0.05).5.Scanning electron microscope observation:The microvilli of the colonic mucosal surface of ultra-short intestine rats group obvious gaps variable length,increased in the number,spacing narrowed,comparing with control and blank-control groups;The density of ultra-short intestine rats' microvilli increased,with circular top,mutual stick together,and gap between narrowed,and mucosal absorptive cell hyperplasia significantly.Ultra-short intestinal rats showed that the same area of colonic mucosa absorption capacity than the sham and control group rats enhanced.6.Transmission electron microscopy observation:Ultra-short intestinal group and the normal control group,apoptosis reduced,colon mucosa goblet cells reduced and absorption of cell increased.At the same time,microvilli change of variable length; adjacent cell membrane with a rugged Structure,connecting cell mosaic,closely connected,desmosome increased ER,Gorky-developed,for instant,significantly increasing the number of mitochondria,the structural integrity.Ultrashort rats showed that intestinal absorption of colon cell absorption,metabolism increased. Sham group and control group showed no significant difference.Conclusion:After entire small intestine resection,the capacity of rat's colon to water,carbohydrate and amino acid absorption enhanced.At the same time,the Morphology of colon mucosa underwent compensatory hyperplasia.Rat colon mucosa reduced due to apoptosis.And the absorption of cell,microvilli,the membrane surface area and mitochondria increased significantly.Overall the morphology and ultrastructural changes of the colon were in the same role in colonic absorption compensatory.