肠易激综合征大鼠模型脊髓后角神经递质表达的改变

Expressions of several neurotransmitters on the posterior horn of spinal cord in the rat model of irritable bowel syndrome

目的利用便秘型肠易激综合征(C-IBS)大鼠模型,对该模型中P物质(SP)、血管活性肠肽(VIP)、γ-氨基丁酸(GABA)、乙酰胆碱、去甲肾上腺素在脊髓后角的分布及表达进行研究,探讨IBS中脊髓后角神经系统在发病机制中的可能作用。方法采用以往本研究小组建立的C-IBS大鼠模型,取模型组及正常对照组大鼠的脊髓后角标本,进行常规组织固定、包埋、切片。分别应用抗SP、VIP、GABA、乙酰胆碱酯酶(AchE)、酪氨酸羟化酶(TH)抗体进行免疫组织化学染色,应用彩色病理图像分析系统对阳性表达的面积、不透光率密度值进行半定量分析。结果C-IBS大鼠模型脊髓后角中SP、AchE表达的阳性面积、不透光率密度值均明显增高(P<0.05);C-IBS大鼠模型脊髓后角中VIP、GABA、TH表达的阳性面积、不透光率密度值与正常对照组无显著差异(P>0.05)。结论C-IBS大鼠模型中脊髓后角SP及AchE表达具有改变,提示脊髓后角中P物质能及胆碱能神经系统可能参与C-IBS的病理生理过程。

Objective To investigate the expressions of the common neurotransmitters in the posterior horn of spinal cord using the rat model of constipation-predominant irritable bowel syndrome （IBS） and to explore the possible roles of the posterior horn of spinal cord in the pathogenesis of IBS. Methods The rat model was set up by intragastric instillation of 2. Oml water at 0-4 ℃ in male Wistar rats for two weeks. Both the model group and the control underwent rectal distention then were deeply anesthetized. Sections containing the anatomical areas of interest were obtained and processed for immunohistochemistry using anti- substance P, vasoactive intestinal peptide, gamma- aminobutyric acid, acetylcholinesterase （AchE） and tyrosine hydroxylase （TH） antibodies respectively, and the staining results were analyzed semi-quantitatively using computerized color image analyzer. The statistical difference of the opacity density and immunoreactive areas between two groups was examined by t-test. Results Immunoreactive area, opacity density of substance P and AchE immunoreactive tissues in the model group were all significantly higher than those in control group （ P 〈 0. 05）, meanwhile there were no differences between the two groups concerning the immunoreactive area, opacity density of vasoactive intestinal peptide, gamma- aminobutyric acid, and TH immunoreactive tissues （ P 〉 0. 05）. Conclusion The expressions of SP and acetylcholine in the spinal cord in the rat model of CIBS are abnormal, which suggests that cholinergic and substance P containing nervous system in the posterior horn of the spinal cord may play some roles in the pathogenesis of IBS.