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背景:内脏高敏感性是肠易激综合征(IBS)重要的病理生理特征,而应激事件能诱发或加重IBS患者的症状。目的:了解急性束缚应激对大鼠结肠敏感性的影响和持续时间,以及对单个平滑肌细胞收缩活动的影响。方法:建立急性部分束缚应激大鼠动物模型,于0天(应激前1天)、1天(应激当天)、2天(应激后1天)行结直肠气囊扩张．并行腹壁回撤反射(AWR)评分;分离平滑肌细胞,测定结肠平滑肌细胞的收缩百分率。结果:20 mm Hg和40 mm Hg扩张压力下,束缚组1天的AWR评分显著高于对照组(1．68±0．79对0．81±0．42、2．45±0．72对1．58±0．60,P<0．05);束缚组大鼠1天时AWR评分在20 mm Hg(P1=0．001;P3=0．006)和40 mm Hg(P2=0．012,P4=0．033)扩张压力下与0天、 2天相比显著增加,但在60 mm Hg和80 mm Hg扩张压力下以及对照组在每天的评分均无显著差异;束缚组结肠平滑肌细胞的收缩百分率与对照组无显著差异(P=0．523)。结论:急性束缚应激使大鼠结肠对低压力球囊扩张的敏感性呈一过性增加,对大鼠单个平滑肌细胞的收缩活动没有影响。
BACKGROUND: Visceral hypersensitivity is an important pathophysiologic feature of irritable bowel syndrome (IBS), and stressful events can induce or exacerbate symptoms in patients with IBS. OBJECTIVE: To investigate the effect and duration of acute restraint stress on colonic sensitivity in rats and its effect on contractile activity of single smooth muscle cells. Methods: The animal model of acute partial restraint stress was established. The colorectal balloon was dilated on day 0 (one day before stress), one day (stress day) and two days (one day after stress). Parallel abdominal wall retraction reflex (AWR) score; isolated smooth muscle cells were measured percentage of colon smooth muscle cells. RESULTS: At 20 mm Hg and 40 mm Hg dilational pressure, the AWR score was significantly higher in the shackle group than in the control group (1.68 ± 0.79 vs 0.81 ± 0.42, 2.45 ± 0.72 vs. 1.58 ± 0.60, P <0.05). The AWR score of sham operation group at 20 mm Hg (P1 = 0.001; P3 = 0.006) and 40 mm Hg , P4 = 0.033) at day 0 and day 2 under dilatation pressure, but there was no significant difference in dilation pressure at 60 mm Hg and 80 mm Hg and in the control group on a day-to-day basis. The binding group of colonic smooth muscle cells (P = 0.523) compared with the control group. CONCLUSION: Acute restraint stress induces a transient increase in the sensitivity of the colon to low-pressure balloon dilatation and has no effect on contractile activity of single smooth muscle cells in rats.