高强度聚焦超声作用下兔脑的病理转归

Pathological regression at the focus in normal New Zealand Rabbits' brain tissue after high intensity focused ultrasound ablation

目的:通过研究高强度聚焦超声(High intensityfocused ultrasound,HIFU)对正常兔脑组织作用后损伤灶的病理转归,探讨其治疗脑肿瘤的安全性和可行性。方法:选取合适的HIFU作用剂量,对12只新西兰兔左右两侧脑组织分别照射5s和10s,于即刻、3天、7天、14天、28天及60天处死取材,大体和组织学观察照射后损伤灶的生物学特性及靶区组织病理学变化,并在电镜下观察损伤即刻的超微结构变化。结果:大体与光镜观察发现在作用时间为5s和10s的不同情况下,二者损伤程度以28天差异最大,最终10s区转归为神经胶质瘢痕,5s区则未见明显损伤痕迹。在HIFU损伤即刻,电镜下可见10s区出现细胞、血管结构完整性受破坏,而5s作用区仍具有完整性。结论:HIFU能定位损伤大脑深部组织,对浅表组织的影响较小。损伤灶的修复方式与照射的剂量有关,提示用适当剂量HIFU治疗脑肿瘤是安全的和可行的,为将来应用HIFU临床治疗脑肿瘤提供了实验依据。

Objective： To determine if HIFU is secure and effective for the treatment of intracranial neoplasm by observing pathological regression at the focus in normal New Zealand Rabbits＇ brain tissue after ablation. Methods： We selected suitable doses of exposure to ab-late 12 rabbits＇ brain tissue, and sacrificed them successively at 1, 3, 7, 14, 28 and 60 days（d） after sonication, observing target lesions grossly and microscopically to identify the biological characteristic and pathologic changes. The ultra-structural changes were also observed immediately after sonication. Results： We took the 5s and 10s for each exposure time in the studies. Different ranges of lesions were pro-duced after different exposure time, especially on 28d, although grossly and microscopically the lesion were almost the same in early period. Finally the lOs sonicated area regressed to scar of glia, but no apparent lesion was found in the 5s area. Ultra-structural examination showed the integrity of cell and vascular structure were destructed in lOs area, but remained intact in 5s area. Conclusion： HIFU could ab-late deep localized brain tissue with little effect on the superficial brain tissue. The restoring mode of sonicated lesion is correlated with ex-posed doses, and it is reversible when using suitable dose of exposure. In conclusion, it is secure and effective to use suitable dose of HIFU in the treatment of intracranial neoplasm and some experimental data are provided for future clinical investigation.