| [Objective]To explore the pathogenesis of slow transit constipation complicated with adult megacolon by detecting the expression of neuron specific enolase(NSE), specific marker C-kit receptor of interstitial cells of Cajal(ICC) and connexin43(Cx43),further discussing the clinical significance of ganglion cells, ICC and Cx43 in slow transit constipation complicated with adult megacolon.[Methods]The paraffin-embedded specimens of 21 cases of above patients admitted performed by subtotal colectomy and modified Duhamel anastomosis from January2009 to February 2015 in the People’s Hospital of Hunan Province were collected.The case group composed of a proximal margin group, a distal margin group and a dilated segment group. Another 10 normal segments(a control group) were also collected. All specimens were fixed in 10% neutral formalin, conventional dehydrated,and paraffin-embedded. Three serial sections were obtained from each paraffin block and immunohistochemical staining(Eli Vision) was used to detect the proteins of NSE,C-kit and Cx43. The distribution of ganglion cells, ICC and Cx43 positive cells in intestinal wall was observed by light microscope and the number of above cells admitted were counted and analyzed.[Results]1 NSE, C-kit and Cx43 expression and histological observation 1.1 Intestinal wall of proximal margin Compared with intestinal wall of normal colon, there were no significant differences in the morphology, number and distribution of ganglion cells. The number and distribution of all kinds of ICC were close to that of normal colon. The distribution of Cx43 positive cells was similar to that of normal colon, but Cx43 expression in the circular muscle layer was significantly stronger than that in the longitudinal muscle layer and the submucosal layer. Mean number of ganglion cells,ICC and Cx43 positive cells were 13.571±2.481, 19.29±5.44 and 52.38±7.32 per HPF.1.2 Intestinal wall of distal margin The myenteric and submucosal plexus were obviously thickened, in which nerve fibers were found significant proliferation and disordered. Ganglion cells in the region of the myenteric plexus were scarce or a few degenerated ganglion cells were occasionally observed, while ganglion cells in the submucosal plexus were absent.The number of various types of ICC was significantly decreased or even absent.Several IC-MY scattered in intestinal wall around the myenteric plexus and normal cellular network disappeared. A few ICC in the circular muscle layer were occasionally observed far spaced, meanwhile tight junction disappeared, while ICC in the longitudinal muscle layer and IC-SM almost completely disappeared. Cx43 expression was significantly decreased in all layers of intestinal wall. Mean number of ganglion cells, ICC and Cx43 positive cells were 0.476±0.814, 3.05±1.96 and3.95±3.46 per HPF.1.3 Intestinal wall of dilated segment The number of ganglion cells decreased, mainly located in the region of the myenteric plexus. The number of various types of ICC was less than that of normal colon, especially in the longitudinal muscle layer and IC-SM. There were large differences in the distribution of ICC, mainly located in the region of the myenteric plexus, which surrounding the myenteric plexus to form a discontinuous distribution and thus formed a incomplete cellular network. Cx43 positive cells were observed in the region of the myenteric plexus and the circular muscle layer, while there was rare or even no Cx43 expression in the longitudinal muscle layer and the submucosal layer. Mean number of ganglion cells, ICC and Cx43 positive cells were7.000±4.135, 9.62±5.31 and 26.71±9.28 per HPF.1.4 Intestinal wall of normal colon In intestinal wall, the morphological structure of the myenteric plexus was basically identical with that of the submucosal plexus. Ganglion cells were clearly visible and similar in morphology and volume, meanwhile nerve fibers was not found thickening in the myenteric and submucosal plexus. Lots of ICC were observed in the peripheral of the myenteric plexus(IC-MY), located in the interspace between the circular muscle layer and the longitudinal muscle layer, and connected with each other through protrusions to form cellular network. A number of ICC were observed in the circular and longitudinal muscle layers(IC-IM), bead curtain like located in the gap of muscle, which were close to and parallel with smooth muscle cells. Some of ICC were observed in the interspace between the submucosal border and the circular muscle layer(IC-SM) and connected with each other through protrusions. Cx43 positive cells were mainly distributed in the region of the myenteric plexus and the circular muscle layer, connected with each other to form a network construction, while Cx43 expression in the longitudinal muscle layer and the submucosal layer was rare. Mean number of ganglion cells, ICC and Cx43 positive cells were 14.800±1.814,21.30±3.59 and 55.40±5.68 per HPF.2 Comparison of NSE, C-kit and Cx43 expression in different intestinal segments There was no significant difference in NSE, C-kit and Cx43 expression in intestinal wall between proximal margin group and control group(P>0.05), while the differences between distal margin group and control group or dilated segment group and control group were statistically significant(P<0.001). There were significant differences in NSE, C-kit and Cx43 expression in intestinal wall between proximal margin group and distal margin group or dilated segment group and distal margin group(P<0.001), meanwhile the difference between dilated segment group and proximal margin group was statistically significant(P<0.001).[Conclusion]The pathological changes of slow transit constipation complicated with adult megacolon were the absence of ganglion cells, the reduction of ICC and the destruction of gap junction structure with the expression of NSE, C-kit, Cx43 decreased. Expression of NSE, C-kit and Cx43 may be used as indicators for evaluating the therapeutic effect of surgery in slow transit constipation complicated with adult megacolon. |
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