摘要： 目的·观察蛋白酶激活受体2（protease activated receptor 2，PAR2）对慢性应激小鼠结肠运动的影响，并探究其作用机制。方法·通过慢性多源应激构建慢性应激小鼠模型。分离小鼠结肠平滑肌，通过肌条收缩实验和Western blotting，观察PAR2激动剂和小电导钙激活钾通道3（small conductance calcium-activated potassium channel 3，SK3通道）阻断剂对结肠运动的影响，以及血小板衍生生长因子受体α（platelet-derived growth factor receptor α，PDGFα）、SK3通道、PAR2表达情况。使用
t检验进行统计学分析，
P<0.05认为差异有统计学意义。结果·小鼠应激刺激结束24 h粪便排出量明显减少；慢性应激小鼠结肠平滑肌组织PAR2表达增加，PAR2受体激动剂对结肠平滑肌运动的抑制作用在慢性应激小鼠更加明显；慢性应激小鼠结肠平滑肌组织PDGFRα表达增加，但SK3表达没有明显变化；SK3通道阻断剂对结肠平滑肌运动的抑制作用在慢性应激和对照组小鼠之间差异无统计学意义。结论·慢性应激使小鼠结肠运动减弱且传输减慢，可能与慢性应激引起的PAR2表达增多、功能上调有关。
关键词: 应激, 蛋白酶激活受体2, 血小板衍生生长因子受体α阳性细胞, 结肠运动, 小电导钙激活钾通道 Abstract: Objective·To observe the effect of protease activated receptor 2 (PAR2) on colonic motility in chronic stress-treated mice, and investigate its mechanism.
Methods·The mice were treated with chronic heterogenous stress for 14 days to establish the chronic stress model. Western blotting was used to determine the expressions of PAR2, platelet-derived growth factor receptor α (PDGFRα) and small conductance calcium-activated potassium channel 3 (SK3 channel), while the effects of PAR2 agonist and SK3 channel antagonist on colonic motility were observed by isometric tension experiment. T-test was used for statistical analysis. Statistical significance was accepted at the value of P<0.05.
Results·Twenty-four hours after being treated by stress stimulation, the mice demonstrated a decrease of colonic transmission because the number of fecal pellets decreased significantly; simultaneously, the expression of PAR2 increased in the colon smooth muscle tissue of chronic stress-treated mice. The inhibition of colonic smooth muscle contractions by PAR2 agonist was more significant in the chronic stress-treated mice than that in the control ones. The expression of PDGFRα in colonic smooth muscle tissue of chronic stress-treated mice increased, but the expression of SK3 had no obvious change, compared with the control mice. The inhibition of colonic smooth muscle contractions by SK3 channel antagonist was not significantly different between chronic stress-treated mice and the control mice.
Conclusion·In the colons of chronic stress-treated mice, PAR2 activity and expression both increase, which may be responsible for the decrease of colonic motility.
Key words: stress, protease activated receptor 2 (PAR2), platelet-derived growth factor receptor α-positive cell (PDGFRα+ cell), colonic motility, small conductance calcium-activated potassium channel (SK3 channel) PDF全文下载地址:
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