不同强度超声破坏微泡对犬心肌组织的生物学效应

目的 探讨不同强度的超声破坏微泡对犬心肌组织的生物学效应,优化出影响心肌微环境的最佳辐照条件.方法 9只健康成年杂种犬随机分成3组,每组3只.静脉输入2 ml微泡造影剂,同时采用频率为1 MHz,强度不同的超声辐照(0.5 W/cm2、1.0 W/cm2、2.0 W/cm2)犬心肌组织,辐照时间为5 min.辐照完毕后即刻处死动物,取局部心肌组织.进行病理组织HE染色和透射电镜观察犬心肌细胞及毛细血管内皮细胞等细胞超微结构改变.结果 0.5 W/cm2超声破坏微泡后心肌组织水肿,无出血;1.0 W/cm2超声破坏微泡后心肌组织轻微出血和少量炎症细胞浸润;2.0 W/cm2超声破坏微泡后心肌组织明显出血,炎症细胞一定程度浸润.结论 不同强度超声破坏微泡造影剂能使犬心肌组织产生不同程度的生物学效应;超声强度在1.0～2.0 W/cm2能在使心肌轻度损伤时引起一定程度的炎症反应.

Bioeffects of canine myocardium under microbubble destruction via diversity of ultrasonic intension

Objective To explore the bioeffects of canine myocardium under microbubble destruction via diversity of ultrasonic intension, in order to optimize ultrasonic intension for experiments. Methods Nine mongrel dogs were randomly divided into 3 groups. Ultrasound (1 MHz) in diversity of different intension (0.5 W/cm², 1.0 W/cm², 2.0 W/cm²) was applied to expose canine myocardium after intravenous injection microbubbles of 2.0 ml. All the dogs were killed after being exposed for 5 min. The myocardium was harvested for HE staining and observed with transmission electron microscope for the tissue microstructures. Results The myocardium of hyperemia, disfiguration and necrosis wer observed in all groups. Myocardial edema but not hemorrhage appeared with 0.5 W/cm² , mild myocardial hemorrhage and slight inflammatory cell infiltration happened with 1.0 W/cm², whereas obvious hemorrhage and certain degree of inflammatory cell infiltration occurred with intension of 2.0 W/cm². With the augmentation of ultrasonic intension, myocardium trend to aggravate. Conclusion Ultrasound of diversity intension can induce different bioeffects of canine myocardium. Ultrasound mediated microbubble destruction with the intensity of 1.0-2.0 W/cm² can provoke a certain degree of inflammatory reaction with mild myocardial damage.