Increased proportion of nitric oxide synthase immunoreactive neurons in rat ileal myenteric ganglia after severe acute pancreatitis

Zhong Lin,Ying Liu,Qinghua Hu,Qinghua Zheng

doi:10.1186/1471-230x-11-127

Abstract

BackgroundSevere acute pancreatitis (SAP) remains a potentially life-threatening disease. Gastrointestinal motility disturbance such as intestinal ileus is seen in every case. By now, the mechanisms of pancreatitis-induced ileus are largely unknown. The main purpose of the present study was to observe changes of nitric oxide synthase-immunoreactive (NOS-IR) neurons in ileal myenteric ganglia in SAP rats with gastrointestinal dysmotility, trying to explore underlying nervous mechanisms of pancreatitis-induced ileus.MethodsTwenty Sprague Dawley rats were randomly divided into sham operated group and SAP group. SAP was induced by retrograde cholangiopancreatic duct injection of 5% sodium taurocholate. Abdominal X-ray and intestinal transit were performed to detect the existence of paralytic ileus and intestinal dysmotility. Pathological damage of pancreas was evaluated. Double-immunolabeling was employed for the whole-mount preparations of ileal myenteric ganglia. The morphology of NOS-IR neurons were observed and the percentage of NOS-IR neurons was calculated based on the total Hu-immunoreactive neurons. Total RNA of ileum was extracted according to Trizol reagent protocol. Neuronal NOS (nNOS) mRNA expression was evaluated by RT-PCR.ResultsThe small intestinal transit index in the SAP group was significantly lower compared with the sham operated group (29.21 ± 3.68% vs 52.48 ± 6.76%, P <0.01). The percentage of NOS-IR neurons in ileal myenteric ganglia in the SAP group was significantly higher than that in the sham operated group (37.5 ± 12.28% vs 26.32 ± 16.15%, P <0.01). nNOS mRNA expression in ileum of SAP group was significantly higher than that in the sham operated group (1.02 ± 0.10 vs 0.70 ± 0.06, P < 0.01).ConclusionsThe increased quantity of NOS-IR neurons in ileal myenteric ganglia and increased nNOS mRNA expression may suggest nNOS over expression as one of the nervous mechanisms of gastrointestinal dysmotility in SAP rat.

Highlights

Severe acute pancreatitis (SAP) remains a potentially life-threatening disease
Statistical analysis using Mann-Whitney nonparametric test showed that the percentage of nitric oxide synthaseimmunoreactive (NOS-IR) neurons in the SAP group was significantly higher compared to the sham operated group (37.5 ± 12.28% vs 26.32 ± 16.15%, P
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Summary

Introduction

Severe acute pancreatitis (SAP) remains a potentially life-threatening disease. Gastrointestinal motility disturbance such as intestinal ileus is seen in every case. Severe acute pancreatitis (SAP) remains a potentially life-threatening disease with a mortatity rate about 16.3% [1]. Experimental studies have revealed that many factors are involved, such as gastrointestinal hormones, neurotransmitters, overproduction of inflammatory mediators, tissue macrophage dysfunction, and endotoxin [6,7,8,9,10,11] Such factors are able to alter gastrointestinal motility by direct effect on smooth muscle cells or indirectly by influencing the neuronal circuits involved in peristalsis [6]

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