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

炎症性肠病中胃肠运动障碍的机制尚未明确。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处理小鼠）中分离的炎症远端结肠的机制。虽然p物质诱导的收缩没有改变，但在dss处理的小鼠结肠中，碳水化合物诱导的收缩有所减少。与NO合成酶抑制剂、L-NMMA、环氧合酶抑制剂、吲哚美辛或atp敏感的K^+通道抑制剂格列本脲孵育前，均未恢复dss处理小鼠结肠中碳水化合物诱导的收缩。在半定量RT-PCR实验和Western blotting分析中，毒蕈碱M_3受体的表达没有变化。GTP或GTP_YS诱导的碳苯酚对收缩因子的Ca^<2+>-致敏作用在β-叶绿素通透性dss处理的小鼠结肠中降低。虽然参与平滑肌中更多n - g蛋白偶联信号的rhoA、ROCK1或ROCK2等蛋白的表达没有改变，但参与平滑肌Ca^<2+>-致敏的功能蛋白CPI-17的表达在dss处理的小鼠结肠中显著降低。这些结果表明，结肠炎小鼠对碳甾醇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。蛋白酶活化受体-2 （PAR-2）在胃肠道中高度表达，被肠内肥大细胞和胰蛋白酶释放的蛋白酶激活。par -2的激活引起结肠平滑肌的松弛，这对运动很重要。为了阐明溃疡性结肠炎模型大鼠结肠运动障碍与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）。在对照大鼠结肠中，胰蛋白酶诱导的碳水化合物（CCh）松弛和高kcl诱导的收缩，经维生素a预处理完全解决。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著降低。在DSS大鼠结肠中，SLIGRL-NH诱导的舒张也有所减弱，但对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，PAR-2激活剂诱导的结肠炎大鼠结肠松弛的抑制可能是由于PAR-2 mRNA表达水平的下调。研究表明，肠道运动障碍至少部分是由于IBD中PAR-2的下调。少

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