Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, China.
Key Laboratory of Hubei Province for Digestive System Diseases, Wuhan, Hubei Province, China.
Neurogastroenterol Motil. 2018 Jul;30(7):e13301. doi: 10.1111/nmo.13301. Epub 2018 Mar 9.
The mechanism underlying gastrointestinal (GI) dysmotility associated with chronic pancreatitis (CP) has not been fully elucidated, and enteric nervous system (ENS) has an important regulatory role in gastrointestinal motor function. The aim of this study is to investigate the effect of ENS in the colonic hypomotility induced by trinitrobenzene sulfonic acid (TNBS) infusion which mimics CP.
Male Sprague-Dawley rats were submitted to CP which was induced by pancreatic infusion of 2% TNBS, or sham group with treatment of equal saline. Three weeks after induction of CP, we pathologically examined the inflammation of pancreas and counted the number of withdrawal events stimulated by Von Frey filaments to evaluate hyperalgesia. The gastrointestinal transit rate was measured using Carbon inkl driving test, and the contraction activities of colonic muscle strip were studied in an organ bath system. The expression of choline acetyltransferase (ChAT) and nitric oxide synthase (NOS) in colonic myenteric plexus (MP) of ENS were investigated by Western blotting and double immunofluorescence staining.
In TNBS-treated group, rats had the signs of chronic pancreatitis 3 weeks after intraductal infusion and had increased sensitivity to mechanical stimulation of the abdomen. For rats with CP, the gastrointestinal transit rate was reduced; in addition, the contractile activities of longitudinal muscle (LM) and circular muscle (CM) strips of distal colon in TNBS group were lower than those in sham group. Immunofluorescence demonstrated that the percentage of ChAT-immunoreactive (IR) neurons in the MP was decreased, but the proportion of NOS-IR neurons in the MP was increased when compared with sham-operated group. Western blotting proved that TNBS infusion down-regulated ChAT but up-regulated NOS expression in the colon MP.
CONCLUSIONS & INFERENCES: Decreased ChAT-IR neurons and increased NOS-IR in the MP of colon ENS may contribute to the pathogenesis of colonic dysmotility in CP.
慢性胰腺炎（CP）相关胃肠动力障碍的机制尚未完全阐明，肠神经系统（ENS）在胃肠运动功能中具有重要的调节作用。本研究旨在探讨 ENS 在三硝基苯磺酸（TNBS）灌注诱导的结肠低动力中的作用，这种模型模拟了 CP。
雄性 Sprague-Dawley 大鼠接受胰腺输注 2%TNBS 诱导 CP，或用等渗盐水处理的假手术组。CP 诱导 3 周后，我们通过胰腺病理学检查评估炎症，并通过 Von Frey 纤维计数刺激撤回事件的数量来评估痛觉过敏。使用碳 ink 驱动试验测量胃肠传输率，并在器官浴系统中研究结肠肌条的收缩活动。通过 Western blot 和双免疫荧光染色研究 ENS 结肠肌间神经丛（MP）中胆碱乙酰转移酶（ChAT）和一氧化氮合酶（NOS）的表达。
在 TNBS 处理组中，大鼠在导管内输注后 3 周出现慢性胰腺炎的迹象，并对腹部机械刺激的敏感性增加。对于 CP 大鼠，胃肠传输率降低；此外，TNBS 组的结肠远端纵行肌（LM）和环形肌（CM）肌条的收缩活动低于假手术组。免疫荧光显示，MP 中 ChAT-免疫反应性（IR）神经元的比例降低，但与假手术组相比，MP 中 NOS-IR 神经元的比例增加。Western blot 证实，TNBS 输注下调了结肠 MP 中的 ChAT，但上调了 NOS 表达。
结肠 ENS 中 ChAT-IR 神经元减少和 NOS-IR 增加可能导致 CP 结肠动力障碍的发病机制。
