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Involvement of inflammatory cells on the dysmotility of gastrointestinal smooth muscles in experimental colitis model animals.

炎症细胞参与实验性结肠炎模型动物胃肠平滑肌运动障碍。

基本信息

批准号：
15580260
负责人：
SATO Koichi
金额：
$ 2.43万
依托单位：
Yamaguchi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

The mechanism of gastro-intestinal dysmotility in the inflammatory bowel disease has not been cleared. In this study, we examined the mechanism involved in the inflamed distal colon isolated from dextran sodium sulphate-induced ulcerative colitis model mouse (DSS-treated mouse). Although substance P-induced contraction was not changed, carbachol-induced contraction was reduced in DSS-treated mouse colon. Pre-incubation with NO synthase inhibitor, L-NMMA, cyclooxygenase inhibitor, indomethacin, or ATP-sensitive K^+ channel inhibitor, glibenclamide, did not recovered the carbachol-induced contraction in DSS-treated moue colon. In semi-quantitative RT-PCR experiments and Western blotting analysis, muscarinic M_3 receptor expressions were not changed. The Ca^<2+>-sensitization of contractile elements induced by carbachol with GTP or GTP_YS was reduced in the β-escin permeabilized DSS-treated mouse colon. Although the expression of proteins, such as rhoA, ROCK1 or ROCK2, that are involved i … More n G-protein coupled signaling in smooth muscles, were not changed, the expression of CPI-17, the functional proteins involved in the smooth muscle Ca^<2+>-sensitization, was significantly decreased in DSS-treated mouse colon. These results suggest that the suppression of carbachol-induced contraction in colitis mouse is attributable at lease partially to the increased activity of myosin phosphatase following the down regulation of CPI-17.Protease activated receptor-2 (PAR-2) is highly expressed in gastrointestinal tract and is activated by proteases released form mast cell and trypsin in intestinal lumen. PAR-2-acitivation induces a relaxation of colonic smooth muscle which is important for the motility. In order to elucidate the relationship of dysmotility of colon in ulcerative colitis model rat and PAR-2, we used the dextran sodium sulphate-induced ulcerative colitis model rat (DSS rat). In the control rat colon, trypsin induced relaxation of carbachol (CCh) and high KCl-induced contraction, which is completely resolved by the pretreatment of apamin. In DSS rat colon, these inhibitory effects of trypsin on CCh and high KCl-induced contraction were significantly reduced. In DSS rat colon, the relaxation induced by SLIGRL-NH was also reduced, but the inhibitory effect of EBIO-1, SK_<Ca> activator, has not been changed. In RT-PCR experiments, the expression of PAR-2 mRNA of colonic smooth muscle decreased in DSS rat from control rat. These results suggest that suppression of PAR-2 activator-induced relaxation in colitis rat colon is attributable to the down regulation of PAR-2 mRNA expression level. It is shown that gastro-intestinal-dysmotility is at least partially due to the down regulation of PAR-2 in IBD. Less

炎症性肠病中胃肠动力障碍的机制尚未明确。在这项研究中，我们检查了从右旋糖酐硫酸钠诱导的溃疡性结肠炎模型小鼠（DSS 治疗的小鼠）中分离出的远端结肠发炎的机制。尽管 P 物质诱导的收缩没有改变，但 DSS 处理的小鼠结肠中卡巴胆碱诱导的收缩有所减少。与 NO 合酶抑制剂 L-NMMA、环氧合酶抑制剂吲哚美辛或 ATP 敏感 K^+ 通道抑制剂格列本脲预孵育，没有恢复 DSS 处理的小鼠结肠中卡巴胆碱诱导的收缩。在半定量RT-PCR实验和Western印迹分析中，毒蕈碱M_3受体表达没有改变。在经β-七叶皂苷透化的DSS处理的小鼠结肠中，由卡巴胆碱与GTP或GTP_YS诱导的收缩元件的Ca 2+ -敏化降低。虽然平滑肌中参与 G 蛋白偶联信号传导的蛋白质（例如 rhoA、ROCK1 或 ROCK2）的表达没有改变，但在 DSS 处理的小鼠结肠中，参与平滑肌 Ca^2+ 敏化的功能蛋白 CPI-17 的表达显着降低。这些结果表明，结肠炎小鼠中卡巴胆碱诱导的收缩的抑制至少部分归因于 CPI-17 下调后肌球蛋白磷酸酶活性的增加。蛋白酶激活受体 2 (PAR-2) 在胃肠道中高表达，并被肠腔中肥大细胞和胰蛋白酶释放的蛋白酶激活。 PAR-2 激活会引起结肠平滑肌松弛，这对于结肠蠕动很重要。为了阐明溃疡性结肠炎模型大鼠结肠动力障碍与PAR-2的关系，我们采用了右旋糖酐硫酸钠诱导的溃疡性结肠炎模型大鼠(DSS大鼠)。在对照大鼠结肠中，胰蛋白酶诱导卡巴胆碱 (CCh) 松弛和高 KCl 诱导的收缩，通过 apamin 预处理可完全解决这一问题。在 DSS 大鼠结肠中，胰蛋白酶对 CCh 和高 KCl 诱导的收缩的抑制作用显着降低。在DSS大鼠结肠中，SLIGRL-NH诱导的舒张也减少，但SK_Ca激活剂EBIO-1的抑制作用没有改变。在RT-PCR实验中，DSS大鼠结肠平滑肌PAR-2 mRNA的表达较对照大鼠降低。这些结果表明，结肠炎大鼠结肠中 PAR-2 激活剂诱导的松弛的抑制可归因于 PAR-2 mRNA 表达水平的下调。结果表明，IBD 中胃肠动力障碍至少部分是由于 PAR-2 的下调所致。较少的