白细胞介素6对豚鼠离体近端结肠平滑肌收缩的影响

Effects of interleukin-6 on the contraction of colonic smooth muscle

目的:研究白细胞介素6(IL-6)对豚鼠近端结肠平滑肌的影响及其机制.方法:观察IL-6对结肠收缩的影响;用河豚毒素(TTX)阻断肠神经后观察不同浓度IL-6对结肠平滑肌收缩的影响;损伤Cajal间质细胞(ICC)后观察IL-6对结肠平滑肌收缩的影响.结果:在带有ICC的近端结肠纵行肌加入IL-6后,结肠平滑肌的收缩振幅增加和频率加快,呈浓度依赖性:加入TTX后,收缩的幅度和频率,同拮抗前相比分别降低和减慢(0.206±0.027 g vs 0.300±0.039 g;9.770±1.711 s vs 8.483±1.113 s:P<0.01,P<0.05):TTX阻断后加入IL-6(80μg/L),振幅增加和频率加快(P<0.01,P<0.05):破坏结肠ICC,收缩幅度和频率分别与损伤ICC后加入IL-6无显著性差异(80μg/L),而与正常结肠收缩振幅和频率有显著性差异(P<0.01).结论:IL-6对豚鼠近端结肠平滑肌的收缩活动有兴奋作用,其兴奋效应主要是通过肠神经元介导.ICC是IL-6对平滑肌兴奋途径的一个不可缺少的中间环节.

AIM： To investigate the effects and mechanism of interleukin-6 on the contraction of colonic smooth muscle. METHODS： Smooth muscle segments with mucosa were removed from the proximal colon of guinea pigs, and were divided into three groups： group A [interleukin-6 （IL-6） was added to Tyrode＇s solution], group B （tetrodotoxin and IL-6 added）, and group C （interstitial cells of Cajal were specially destroyed by methylene blue incubation and intensive illumination）. RESULTS： The amplitude and frequency of contractions were upregulated by IL-6 in a doseindependent manner. The frequency and amplitude of contractions were decreased when the enteric nerve was blocked by tetrodotoxin （0.206 ± 0.027 g vs 0.300 ± 0.039 g; 9.770 ± 1.711 s vs 8.483 ± 1.113 s; P 〈 0.01, P 〈 0.05）. Addition of IL-6 （80 μg/L） after blocking with tetrodotoxin increased amplitude and frequency of smooth muscle contraction （P 〈 0.01, P 〈 0.05）. The contraction of smooth muscle was nearly abolished when interstitial cells of cajal were destroyed by methy-lene blue incubation and intensive illumination （P 〈 0.01）. Although IL-6 was administered, 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 methylene blue and intensive illumination. CONCLUSION： IL-6 was able to promote the contraction of colon smooth muscle. The effects of IL-6 on contraction are mainly induced by the enteric nervous system. Interstitial cells of Cajal play an essential role in the activation of smooth muscle contraction by IL-6.