Expression of nerve growth factor and its receptor in distal rectum of children with anorectal malformations

Abstract

Objective To explore the roles of nerve growth factor (NGF) and nerve growth factor receptor (NGFR) (TrkA,P75NTR) in enteric nervous system of distal rectum of children with anorectal malformations (ARM).Methods Specimens were obtained from 30 (24 males,6 females) children's distal rectum with ARM at our hospital during January 2011 to January 2013; According to the position of malformations,there were high (n =15),intermediate (n =6) and low (n =9).Their average age was 1.4 months (range,2 days to 13 months).One-stage abdominal-perineal anoplasty were performed in 8 cases.Among 13 cases of anoplasty by stages,the procedures included laparoscopic-assisted anorectal pull-through (LAARP) (n =7),abdominal-perineal anoplasty (n =2),posterior sagittal anorectoplasty (n=4) and one-stage anpoerineal plasty (n=9).Distal rectum was collected during operation.The hematoxylin-eosin (HE) staining was used to count the number of submucosal plexus and myenteric plexus of distal rectum.And immunohistochemistry (IHC) and quantitative real-time polymerase chain reaction (qRT-PCR) were employed to detect the expressions of NGF and NGFR in distal rectum of patients with ARM.And the expression level of low ARM was compared with that of intermediate or high ARM.Results HE staining:for patients with low ARM,distal rectum submucous and myenteric plexuses were dense with a large plexus area and a large number of intestinal ganglion cell while the distribution of nerve plexus of patients with intermediate or high ARM were obviously few and scattered.Comparing with low ARM,the number of nerve plexus obviously decreased (1.30 ± 0.82 vs.5.60 ± 1.36,P＜0.01) ; IHC:NGF,TrkA and p75NTR were predominantly distributed in distal rectum submucous and myenteric plexuses,NGF & TrkA in nucleus and cytoplasm and P75NTR in nucleus and cell membrane; NGF,TrkA and P75NTR had abundant expression in patients with low ARM in distal rectum submucous and myenteric plexuses,the expression quantity of patients with intermediate or high ARM obviously decreased.The integral optical density (IOD) was (43.48 ±7.11 vs 3.70 ± 1.21; 18.83 ± 3.65 vs 8.49 ±2.68; 23.39 ± 3.64 vs 7.17 ± 2.28,P＜0.01) ; qRT-PCR:The relative expression of NGF,TrkA and P75NTR mRNA at patients with low ARM was obviously higher than that of intermediate or high ARM's (172.22 ± 104.38 vs 80.38 ± 43.10; 148.78 ± 72.45 vs 73.95 ± 47.43; 122.83 ± 35.45 vs 75.15 ± 20.23,P＜ 0.01).Conclusions NGF,TrkA and p75NTR may play an important role in the development of enteric nervous system in distal rectum of children with ARM. Key words: Digestive system abnormalities; Rectum; Anus; Nerve growth factors; Enteric nervous system