IL-1β对豚鼠离体小肠平滑肌的影响

Effects of interleukin-1β on the contraction of isolated small intestinal smooth muscle from guinea pig

目的研究白细胞介素-1β(IL-1β)对豚鼠小肠平滑肌的影响及机制。方法在距回盲部10cm处取回肠平滑肌标本,分为4组:不同浓度IL-1β剂量对照组;ACH+IL-1β组;TTX+IL-1β组;ICC破坏+IL-1β组。结果IL-1β对豚鼠离体小肠平滑肌收缩的基础张力和振幅有抑制作用,呈浓度依赖性;ACH作用后加入IL-1β(3ng/mL)对ACH收缩无明显抑制作用(P>0.05),预加IL-1β(3ng/mL)后加入ACH的收缩振幅与ACH直接作用相比无显著差异(P>0.05)。TTX阻断肠神经后加入IL-1β(3ng/mL),小肠平滑肌的收缩无明显变化(P>0.05)。破坏小肠ICC,收缩幅度和频率与正常小肠收缩幅度和频率比较有显著性差异(P<0.01),加入IL-1β(3ng/mL)无显著性差异(P>0.05)。结论IL-1β对豚鼠小肠平滑肌的收缩活动有抑制作用,对小肠平滑肌的主要神经兴奋物质ACH无明显急性抑制作用,对ACH的反应性无急性影响。IL-1β舒张小肠的作用主要是通过肠神经元介导,对兴奋神经递质释放有抑制作用。ICC是IL-1β对平滑肌抑制途径一个不可缺少的中间环节。

Objective To investigate the effect and mechanism of interleukin-1β（IL-1β） on the contraction of isolated small intestinal smooth muscle from guinea pig. Methods Smooth muscle segments with mueosa were removed from the ileum far away ileoeecal junction 10 cm, and divided into four groups ： IL-1β added to Tyrode solution ; acetylcholine （ACH） and IL-1β added ; tetrodotoxin （TTX） and IL-1β in a dose-independent manner. The amplitude of contraction precaused by ACH was not influenced by IL-1β （P 〉 0.05 ） , as the same as when addition with IL-1β the contraction caused by ACH was no significant difference with contraction precaused by ACH independly（P 〉 0.05 ）. Influence of IL-1β nearly disappeared after blocking enteric nerve with tetrodotoxin （P 〉 0.05 ）. The contraction of smooth muscle was nearly abolished when interstitial cells of Cajal were destroyed by melene blue incubation and intensive illumination （P 〈 0.01 ）. Although IL-1β was adminis tered, there was no significant difference in the amplitude and frequency of the contraction of smooth muscle segments when interstitial cells of Cajal were destroyed by melene blue incubation and intensive illumination （P 〉 0.05 ）. Conclu- sion IL-1β is able to decrease the contraction of small intestinal smooth muscle. Effects of IL-1β on contraction are mainly induced by the enteric nerve system. Terstitial cells of Cajal play an essential role in the activation of smooth muscle by IL-1β. IL-1β also has no significant acute influence on the contraction caused by ACH.