Biological effect of high intensity focused ultrasound on lymphatic vessels

Abstract

Objective To investigate the use of high-intensity focused ultrasound ( HIFU) to noninvasively produce biological effect in rat lymphatic vessels in vivo, and the feasibility of HIFU in the treatment of chyluria. Methods Thirty-two SD rats were divided into four groups randomly. The right inguinal regions were irradiated and the left served as controls. At the 1st, 3rd, 7th and 30 day after HIFU irradiation, the gross and pathological changes were observed. Results There were acute changes such as the lymphatic vessels rupture and deformation on the experimental sides at 1st and 3rd day after HIFU irradiation. The number of lymphatic vessels was reduced, lumen was occluded, scar formed around the lumen at 7th and 30th day. The lymphatic vessec density (LVD) on the experimental side was significantly decreased as compared with the controls after HIFU irradiation (experimental sides vs controls: 1st day,1.100 ±0.428 vs 1.450 ±0.411 (P＜0.01); 3rd day, 0. 725 ±0. 238 vs 1.575 ±0.362 (P＜0.01);7th day, 0. 375 ± 0. 198 vs 1. 575 ± 0. 249 ( P ＜ 0. 01); 30th day, 0.175 ± 0.198 vs 1. 500 ± 0.400 (P＜0. 01). There was a significant decrease in LVD on the experimental side with the time going (F = 16.669,P＜0.01). However, there was no significant decrease in LVD at the 7th day (P＞0.05).Conclusion HIFU could precisely damage lymphatic vessels of rats and make lumen occlusion finally,suggesting the feasibility of HIFU for chyluria treatment. Key words: Lymphatic vessel; High intensity focused ultrasound; Rat