| Objective Hirschsprung’s disease(HSCR),also known as intestinal aganglionosis, is a kind of neural crest cell sourced congenital intestinal disease, in which the enteric nervous system(ENS)getting early poly-genetic mutations resulting from genetic, environmental, ischemia, hypoxia, toxins,immune factors, infection factors. The basic pathophysiological changes are distal colon spasms in bowel tissue submucosal plexus and myenteric plexuses in full or partial lack of intestinal ganglion cells(IGCS), causing the disordered arrangement of nerve fibers and colon bowel spasticity, losing normal forward peristalsis function, which make the waste hard to go through. Thus, the sedimentation in spastic bowel causes compensatory expansion and proximal colonic hypertrophy, forming megacolon. ENS is a complex, active power and the sensory system formed of gastrointestinal tract with intestinal myenteric plexus and submucosal plexus together, independently adjusting the movement and secretion of intestinal function. HSCR is early gene mutation of ENS or the result of a missing function of it.Neurotensin(NT) is a neurotransmitter secreted by special endocrine function open N cells. It belongs to the ligand dependent transcription factors, playing an important role of adjustment in the central nervous system, cardiovascular, respiratory, digestive, endocrine, immune, and other peripheral function system. Neurotensin receptor 1(NTSR1) is a G protein coupled receptors which has seven transmembrane domain structure and is the highest affinity ligand with NT in the human body of the gastrointestinal tract. Through mediated NTSR1, NT enhance the constriction of the colon, promote colon forward peristalsis and empty the distal colonic. NTSR1 plays an important role in the gut motivation of ENS.In our preliminary study, differentially expressed genes including NTSR1, were detected by the Microarrays and verified by RT-PCR. There are hardly any research in the NT mediated NTSR1 interactions with HSCR whether domestically or abroad. Studies have found that NTSR1 in human normal colon submucosal plexus and myenteric plexuses is positive expression, while the situation of NTSR1’s expression in HSCR is not clear. Further to explore the relationship between NTSR1 and development of HSCR, we utilize the technology of immunohistochemisty to demonstrate the expression of NTSR1 in the colon of patients with Hirschsprung’s disease and preliminary discuss the possible relationship between NTSR1 and the HSCR.Methods A total of 42 patients of HSCR, managed at Department of Pediatric Surgery,Guang Dong Women and Children Hospital from april 2010 to september 2014, were included in this study as the experimental group, of which the resected colon specimens were divided into the narrow,transitional, dilated and normal segments. All the patients received operation treatment for the first time as sporadic cases and showed no other congenital anomalies and syndromes. There are no cases of HSCR in their relatives. All the cases were diagnosed by clinical symptoms, signs, examination of Barium enema and finally confirmed by the H&E stains of full thickness surgical specimens histologically. Then 20 samples from the patients of congenital anal atresiaand intestinal perforation(no HSCR cases and other diseases of the abnormal developmental ENS in their families)were settled as the control group. Tissue samples of experimental group and the control group were selected to detect the protein expression of NTSR1 by immunohistochemisty. Positive expression in the myenteric plexus and the muscle of photos were analysed by Image-pro Plus 6.0.The Statistical Program for Social Sciences, version 13.0,was performed for statistical analysis.Result 1. The regular HE staining:Ganglion cells were not seen and the density of nerve fibers in the myenteric and submucosal increased with little organization in the narrow segments.The distribution of ganglion cells were reduced and the abnormal nerve fibers increased from the normal segments to the narrow segments. 2. In normal segments and control group, NTSR1 immunohistochemical staining were mainly strongly positive in the submucosal plexus and the myenteric plexus. Positive nerve cells were not seen in the narrow segments, but there were several positive or negative nerve fibers. Positive myenteric plexus existed in the transitional and dilated segments. The average optical density were compared between the narrow, transitional, dilated and normal segments. 3. NTSR1 to moderate expression was weakly positive in each segment HSCR intestinal smooth muscle, which in general is higher than the expression of the circular muscle longitudinal muscle. 4.Quantitative analysis: NTSR1 narrow segment HSCR experimental group,transitional segment, expansion section, normal segment and group mean optical density of the myenteric plexus expression were 8.39 ± 2.68,11.76 ± 6.79,17.14 ± 12.26,21.92 ± 14.68,23.45 ± 19.82,the statistical software analysis, compared with the transitional segment, the expansion section, normal intestinal tissue segment and the control group, the average optical density of the stricture significantly lower, the difference was statistically significant(P <0.05); transitional section and expansion section average optical density transition segment and normal segment and the expansion segment between segments compared with the normal, no significant difference(P> 0.05).Conclusion 1.The expression of NTSR1 protein in narrow segments was significantly reduced, and the insufficiency or absence expression of NTSR1 protein could affect the enteric nervous pathway integrity and eventually lead to the loss of HSCR in motility. 2. Most of the Neurotensin receptor 1immunohistochemical staining was obvious negative both in the myenteric plexuses in the narrow segments of HSCR. It might help in the observation or interpretation of colon biopsies and can serve as a simple and sensitive diagnosis of HSCR.. |
PDF Full Text Request