Alterations Of Enteric Nervous,Smooth Muscles,Intersti－Tial Cells Of Cajal In Human Intestinal Atresia And Their Clinical Significance

Objective: Through investigating the alterations of enteric nervous, smooth muscles and interstitial cells of Cajal(ICCs) in the resected intestines from patients with intestinal atresia(IA),this study was to discuss the mechanism of postoperative intestinal dysmotility in IA cases,and to explore the range of resected intestinal segments in primary operation. Methods: Fifteen cases of IA were studied. Specimens were taken from the resected intestinal segments proximal and distal to atresia.Six controls were obtained from postmorten neonates without gastro–intestinal or neuroal system diseases.All specimens were stained with haematoxylin and eosin(HE) to count the number of myenteric plexus(MP) and the number of ganglion cells under light microscope.In addition, all specimens were processed for SP immunohistochmistry by using different monoclonal antbody to S-100 protein,toа-smooth muscle actin(а-SMA) and to c-kit protein,then the levels of the expression were semiquantitated respectively. Results:Reduction of MP,ganglionic cell and intramuscular nerve fibers were observed in proximal segments of IA. Changes of MP and ganglionic cell extended all longth of resected proximal segments,but showed a tendency on the incresse at the farther of atresia.Little changes was observed in proximal segments at 16cm from atresia in this study. Intramuscular nerve fibers were normal at 14cm from atresia. A remarkably reduced staining intensity forа-SMA was mainly observed in highly hypertrophic circular muscle layer of the proximal segments. Staining intensity forа-SMA became stronger with hypertrophy of circular muscle layer relieving.At 16cm proximally from atresia, expression ofа-SMA in circular muscle layer seemed normal. Slightly reduced immunoreactivity for а-SMA occurred in muscularis mucosae and longitudinal musculature,but it only extended within 6cm proximal segment.In 3 IA cases,vacuolization was detected occasionally only in proximal circular smooth muscle.Some parts of circular smooth muscle with vacuolization were thinning. Almost no ICCs were observed within 10cm proximally from atresia.Then ICCs around the MP increased. At 16cm proximally from atresia ,a few ICCs were detected around the MP,but still no ICCs were seen in other parts of intestinal wall.In distal segment of IA,the alteration patterns of neuroal and musccular elements and ICCs were similar to the proximal segment,but the level and the range were markedly slight. The distal segment beyond 4cm from atresia seemed normal. No vacuolization was detected in distal circular smooth muscle. Conclusion: Hypoplasia of intramural nerves and ICCs was seen in the proximal and distal segments of IA.Hypertrophy and reduced immunorea-ctivity for а-SMA were observed predominantly in the circular muscle layer of the proximal segment.These alterations of the proximal and distal segments may contribute to the postperative intestinal dysmotility in IA cases.Most of these alterations became slight,when the intestinal range was beyond 16cm proximal and 4cm distal segments from blind end respectively,which should be the range of resected intestinal segment of IA in primary operation.