Effect of focused ultrasound on morphology of nasal mucosa of sheep / 中国耳鼻咽喉头颈外科

ABSTRACT

OBJECTIVE To study the influence of focused ultrasound on the morphology of nasal mucosa in sheep. METHODS A model CZB ultrasound therapeutic system for rhinitis, developed and produced by Chongqing Haifu(HIFU)Technology Co.,Ltd.,Chongqing China,was used in this study. Linear scans were performed on bovine liver in vitro under different scan parameters, and the biologic focal field(BFF)was detected to evaluate if it met the requirements of designed. The nasal mucosa of inferior turbinate of sheep was exposed with the same scan parameters under the observation of nasal endoscope, and morphological changes of the nasal mucosa were observed by gross examination, light and electron microscopes. RESULTS This study revealed that the designed biological focal field in bovine liver in vitro could be obtained under the scan parameters mentioned above. Linear scan with the same condition,there was no obvious change in appearance and color of the treated nasal mucosa in the inferior turbinate of the sheep. However,3 days after treatment,there was an increased secretion in the nasal cavity,which recovered 7 days post-treatment. Light microscopic examination 3 days after exposure showed that the epithelia of the nasal mucosa was intact and there was diffused distribution of spot coagulated necroses in the subepithelia layer of treated nasal mucosa. Degeneration of vascular endothelial cells and thrombosis of blood vessels were found in the coagulated necrosis region. Besides,degeneration or necrosis of nerve cells was induced,and glandular cells werepartially or completely damaged. The structure of epithelial goblet cells and ciliated cells in the treated nasal mucosa appeared to be normal under the observation of electronic microscope. At the seventh day after treatment,signs of tissue regeneration such as hyperplasia of collagen fiber were found in the coagulated region,and the necrosis tissue began to dissolve and was absorbed at the 14th day post-treatment. CONCLUSION Under the above scan parameters,the energy of focused ultrasound could be deposited specifically at the subepithelia layer,and to ablate the targeted nasal mucous tissues which are rich in blood vessels,nerves and glands. There were no damage to the non-target area such as epithelial layer,which could maintain the normal structure and biological function of mucociliary of nasal mucosa.