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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发生机制尚不清楚。在这项研究中，我们研究了从葡聚糖硫酸钠诱导的溃疡性结肠炎模型小鼠（DSS治疗小鼠）中分离的远端结肠炎症的机制。虽然P物质诱导的收缩没有改变，卡巴胆碱诱导的收缩减少DSS治疗的小鼠结肠。用NO合成酶抑制剂L-NMMA、环氧合酶抑制剂吲哚美辛或ATP敏感性K^+通道抑制剂格列本脲预孵育，不能恢复DSS处理的小鼠结肠中卡巴胆碱诱导的收缩。半定量RT-PCR和Western blotting分析表明，M_3受体的表达无明显变化。在β-七叶皂苷透化的DSS处理的小鼠结肠中，卡巴胆碱与GTP或GTP_YS诱导的收缩元件的Ca^<2+>敏感性降低。虽然相关蛋白质如rhoA、ROCK 1或ROCK 2的表达， ...更多信息在DSS处理的小鼠结肠中，平滑肌中的G蛋白偶联信号没有改变，而参与平滑肌Ca^2+敏化的功能蛋白CPI-17的表达显著降低。这些结果表明，结肠炎小鼠对卡巴胆碱引起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）在胃肠道中高度表达，并被肠腔中肥大细胞释放的蛋白酶和胰蛋白酶激活。PAR-2激活诱导结肠平滑肌松弛，这对于运动是重要的。为了探讨溃疡性结肠炎模型大鼠结肠动力障碍与PAR-2的关系，我们采用葡聚糖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，胰蛋白酶引起的氨甲酰胆碱（CCh）和高氯化钾引起的收缩，这是完全解决的预处理的蜂毒肽。在DSS大鼠结肠中，胰蛋白酶对CCh和高KCl引起的收缩的这些抑制作用显著降低。在DSS大鼠结肠，SLIGRL-NH引起的舒张作用也减弱，但SK_1激活剂EBIO-1的抑制作用<Ca>没有改变。RT-PCR结果显示，DSS大鼠结肠平滑肌PAR-2 mRNA的表达较对照组明显降低。这些结果表明，抑制PAR-2激活剂诱导的结肠炎大鼠结肠舒张是由于PAR-2 mRNA表达水平下调。表明IBD时胃肠道动力障碍至少部分是由于PAR-2下调所致。少