目的 研究低强度超声对大鼠肠管平滑肌收缩的影响,找出超声引起肠管平滑肌收缩的适宜辐照参数.方法 采用频率固定、声强可进行选择的低强度超声(频率600 kHz,声强为10.8、14、18W/Cm2)分别辐照离体和活体的大鼠肠管,采用BL410生物机能实验系统记录离体肠管平滑肌的收缩情况,用亚甲监推进实验来观察大鼠活体肠管的收缩变化.结果 离体实验表明超声辐照大鼠肠管的收缩频率、幅度、张力及活动力均明显高于辐照前(P＜0.05),辐照停止1 2 min左右,肠管收缩与辐射前状态基本保持一致；在l 4 W/cm2,辐照7 min时,肠道收缩的频率、幅度、活动力达到最大(P＜(0.05).活体实验表明辐照后各组大鼠肠管内亚甲蓝移动率明显高于对照组(P＜0.05)；在14 W/cm2,辐照7 min时亚甲蓝移动率较对照组的差异明显高于其余各组(P＜0.05).结论 低强度超声对大鼠肠管平滑肌收缩有一定影响,在频率为600 kHz时,14 W/cm2,辐照7 min是适宜的辐照参数.%Objective To study the influence of low intensity ultrasound on the contraction of intestinal smooth muscle in rats in order to find suitable exposure parameters of the contraction. Methods The in vitro/vivo rat intestine were taken out and irradiated by ultrasound at different intensities and for exposure times (600 kHz. 10. 8,14,18 W/cnr). The contraction frequency and amplitude were recorded with BL -110 biological experimental system, while Methylene blue propulsion experiment was carried out for the in vivo observation. Results It was demonstra'ed in the in vitro experiment that the contraction frequency, amplitude, tension and activity were significantly increased during ultrasonic irradiation( P<0. 05)compared with no irradiation. The increased contraction frequency and amplitude lasted for about 12 min.and then the normal contraction pattern was resumed. When the intensity of 14 W; cm' ultrasonic irradiation lasted for 7 min.the contraction frequency,amplitude,tension and contraction activity peaked(P<0. 05). The in vivo experiment demonstrated the motility of meihylene blue in all the groups ol rat intestine irradiated was distinctly higher than that in the control group, while in the condition of 14 W/cnr and 7 min. the motility discrepancy of methylene blue compared with the control group was bigger than the other groups (P<0. 05). Conclusions Low m tensity ultrasound has a certain influence on intestinal smooth muscle contraction in rats. With the frequency of 600 KHz.the suitable parameter is 14 W/cm ultrasonic irradiation for 7 min.
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