低强度超声对大鼠痛经模型的镇痛作用及其机制

目的观察低强度超声辐照对大鼠痛经模型的镇痛效应。方法将75只3月龄动情间期的雌性SD大鼠随机平均分为盐水组、模型组、超声组。采用苯甲酸雌二醇和缩宫素联合制备痛经大鼠模型，盐水组以等量生理盐水进行处理。建模成功后，超声组给予低强度超声辐照（频率200kHz，声强0．2w／cm^2）腹部10min，模型组和盐水组不予超声处理。观察辐照后20min内大鼠扭体行为，记录子宫收缩波，检测子宫β-内啡肽（β-EP）水平。结果与模型组比较，超声组大鼠扭体潜伏期显著延长，扭体次数、评分均显著降低（P〈0．01）；子宫收缩频次变化差异无统计学意义（P〉0．05），子宫收缩波幅、张力、活动度均显著性降低（P〈0．05）；子宫β-EP含量显著增加（P〈O．01）。结论低强度超声辐照对大鼠痛经模型具有显著镇痛效应。

Analgesic effect and mechanism of low-intensity ultrasound in dysmenorrhea rats

Objective To observe the analgesic effect of low-intensity ultrasound in dysmenorrhea rats. Methods Seventy-five female SD rats aged 3 months in the diestrus were randomly allocated into saline group, model group and ultrasonic group. The rats in the model group and ultrasonic group were given estradiol benzoate combined with oxytocin to prepare the models of dysmenorrhea, while in the saline group were given the same dose of saline. Then the model group and saline group were not to deal with ultrasonic irradiation, ultrasonic group were treated with ultrasonic irradiation （frequency 200 kHz, intensity 0.2 W/cm^2） of the abdomen for 10 min. The writhing response of the rats and the wave forms of uterine contraction were observed after ultrasonic irradiation, and changes of β-endorphin （β-EP） in rat uterus were observed with Elisa. Results Compared with model group, the writhing latency of rats in ultrasonic group extended significantly （P 〈0.01）, the writhing numbers and score decreased significantly （both P〈0. 01）. In terms of the wave forms of uterine contraction, after ultrasonic irradiation, the amplitude, tension and the activity of uterine contraction decreased significantly （P〈0. 05）, but no statistical difference of frequency of uterine contraction was found （P〉0. 05）, while uterine β-EP level increased considerably （P〈0.01）. Conclusion Low-intensity ultrasound have analgesic effect in dysmenorrhea rats.