大鼠直肠注入辣椒素内脏痛模型的建立

A VISCERAL PAIN MODEL DEVELOPED BY INTRARECTUM INSTILLATION OF CAPSAICIN IN RAT

为了建立操作简捷、内脏痛特异的大鼠行为学模型,本研究将生理盐水和辣椒素(capsaicin,CAP)直接注入大鼠直肠,通过计数内脏痛相关行为的数目以及HE染色来观察CAP刺激直肠后大鼠行为学和直肠形态学的变化;行为学指标用VonFrey纤维测量大鼠后足底、尾根部以及腹部的机械刺激阈值。结果显示:(1)与生理盐水对照组相比,将CAP注入大鼠直肠可引起即刻强烈的内脏痛反应(P<0.05),该痛觉反应主要集中在直肠注入辣椒素后20min内;(2)大鼠直肠注入CAP60min后,直肠粘膜下层明显水肿;后足底、尾根部以及腹部的机械刺激阈值较直肠注入CAP前明显升高。上述结果表明:直接将CAP注入直肠可致大鼠直肠水肿并引起内脏痛觉,可根据大鼠直肠直接注入CAP后的行为变化建立内脏痛模型。

To develop a simple visceral pain-specific behavioral model in the rat, saline and different concentrations of capsaicin （CAP） were administrated through a fine cannula with a rounded tip introduced into the rectum via the anus. The number of visceral pain-zelated behaviors was calculated and HE staining was adopted to examine the behavioral and morphological changes after intrarectum instillation of CAP. Von Frey hairs of different intensities were applied to determine the threshold of different body areas to mechanical stimulation. The results showed： （ 1 ） Compared with the saline-treated rats, intrarectum administration of CAP （ 10 -5 tool/L, 10^-4 mol/L and 10^-3 tool/ L） evoked greater visceral plan-related behaviors, which wine mainly displayed within 20 min post administration of CAP. （2） Sixty rain after administration of CAP, edema in rectum was observed, and the threshold of the body areas tested to mechanical stimulation was commonly higher than that observed before instillation. The results suggest that intrarectum instillation of CAP in rat can evoke edema in rectum and visceral pain-related behavioral changes. Thus, relying on the changes of pain-related behaviors, a visceral pain model can be developed.