海马N-乙基马来酰亚胺敏感因子在肠易激综合征大鼠中的作用

The Role of Hippocampal NSF in Rats with Irritable Bowel Syndrome

摘要:

目的:探究海马N-乙基马来酰亚胺敏感因子(N-ethylmaleimide sensitive factor, NSF) 在慢性功能性内脏痛大鼠中枢敏化中的作用及机制。方法:①建立IBS模型大鼠：新生SD乳鼠出生d3~21，每天固定时间给予3小时的母婴分离。对照组乳鼠不做任何处理，正常饲养。待大鼠生长至8周，检测大鼠腹外斜肌对40mmHg和60mmHg结直肠扩张引起的放电反应，评估大鼠的内脏痛觉敏感性。②免疫印迹法检测大鼠海马NSF的表达。③大鼠行海马脑立体定位置管，双侧海马CA1微量注射不同剂量的NSF的特异性抑制剂pep2m，比较给药前后腹外斜肌放电反应的差异。④用含有pep2m的人工脑脊液灌流脑片60min，取海马组织，免疫印迹法检测AMPA受体GluR2亚型的表达。结果: ①与正常大鼠相比较，IBS模型大鼠海马NSF表达显著增高；②海马双侧微量注射pep2m可剂量依赖性抑制IBS模型大鼠内脏痛觉敏感性；③用含有pep2m的人工脑脊液灌流脑片后，IBS模型大鼠海马GluR2表达显著降低。结论: 海马NSF可通过增强AMPARs-GluR2 的功能，诱导慢性功能性内脏超敏反应。

Abstract:

Objective: To explore the roles of hippocampal N-ethylmaleicimide sensitive factors (NSF) in the central sensitization of irritable bowel syndrome (IBS) like rats. Methods:①IBS rats were established by neonatal maternal separation (NMS) during post-natal days 3-21 and each one was put in cubicles separately for 3 h daily. The control rats were treated like IBS rats except NMS. The visceral hypersensitivity was assessed by recording the responses of the external oblique abdominal muscle to 40 and 60mmHg colorectal distention (CRD) when the rats were adult (8 weeks). ②The levels of hippocampal NSF were detected by the method of Western blot. ③The effects of NSF on visceral hypersensitivity were examined by the electromyogram (EMG) after the bilateral intrahippocampal injections of pep2m (a NSF specific inhibitor). ④The expression of GluR2 (one of AMPARs subtype) were tested by Western blot after the hippocampal slices were perfused with pep2m for 60 minutes. Results:①The expressions of hippocampal NSF significantly increased in IBS rats compared with control rats. ②Bilateral intrahippocampal injections of pep2m dose-dependently attenuate the visceral hypersensitivity in IBS like rats. ③After the hippocampus slices were perfused with pep2m, the expression of GluR2 decreased significantly in IBS rats, but there were no obvious change in control rats. Conclusion:Hippocampal NSF could induce chronic functional visceral hypersensitivity by enhancing the functions of AMPARs-GluR2.