Influence of high intensity focused ultrasound irradiating cornea on retinas of living rabbits

Authors: Li Meixuan,  Du Zhiyu,  Wang Menglei,  Yan Pisong,  Zhang Yu,  Li Chongyan

 DOI: 10.3760/cma.j.issn.2095-0160.2017.06.005
Published 2017-06-10
Cite as Chin J Exp Ophthalmol, 2017,35(06): 506-511.

Abstract

Background

High intensity focused ultrasound (HIFU) is a novel noninvasive technique and it has been used to clinical treatment of solid tumors.However, whether it is safe to cure eye related diseases has not been reported.

Objective

This study was to explore the influence of HIFU on retinas of living rabbits after the irradiation on cornea, and provide a theoretical basis for the safety of clinical therapy.

Methods

Forty-one rabbits were involved.The corneal stroma of the right eye was irradiated by HIFU that was fixed in circular shape.The left eye with no treatment served as control group.Six rabbits were sacrificed at day 1, 7, 14, 30, 60 and 90 days after irradiation, respectively.The eyeballs of 3 rabbits were collected for paraffin imbedding.Histological method was then used to evaluate the structure of retina.Immunohistochemistry was used to determine the expression of Nogo-A.TUNEL method was carried out to examine cell apoptosis of different layers of retina.The retina of the rest 3 rabbits were collected to determine the contents of superoxide dismutase (SOD) and malondialdehyde (MDA). The retinal morphology of 5 rabbits were scanned by OCT and retinal thickness was recorded before irradiation and 1, 7, 14, 30, 60 and 90 days after irradiation.The use and care of experimental animals complied with Regulations on the Administration of Experimental Animals from National Ministry of Science and Technology.

Results

The number of retinal cell layers remained intact in the cornea of living rabbits after HIFU irradiation.The structure of each layer was densely and orderly arranged with clear borders between layers.The histological morphology of retinal tissues were the same among control eyes and experimental eyes at different time points.There was no significant difference in Nogo-A expression among control eyes and experimental eyes at different time points (Fgroup=0.672, P=0.413; Ftime=1.622, P=0.157). No significant difference was obtained in SOD activity and MDA contents among control eyes and experimental eyes at different time points (SOD: Fgroup=0.167, P=0.684; Ftime=0.074, P=0.996.MDA: Fgroup=0.005, P=0.946; Ftime=0.405, P=0.844). No TUNEL positive cell was obtained in each group.The thickness of retinal tissues showed no significant difference among before irradiation and 1, 7, 14, 30, 60 and 90 days after irradiation (F=0.150, P=0.988).

Conclusions

The irradiation of HIFU on the cornea of living rabbits shows no significant influence on the morphology and bioactive factors of retina.Therefore, the therapeutic application of HIFU irradiation on cornea is safe for retina.

Key words:

High intensity focused ultrasound; Retina; Superoxide dismutase; Malondialdehyde; Nogo-A

Contributor Information

Li Meixuan
Department of Ophthalmology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
Du Zhiyu
Department of Ophthalmology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
Wang Menglei
Department of Ophthalmology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing 400010, China
Yan Pisong
Chongqing Medal Eye Institute, Chongqing 400050, China
Zhang Yu
Chongqing Medal Eye Institute, Chongqing 400050, China
Li Chongyan
State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and Ministry of Science and Technology, Chongqing Key Laboratory of Ultrasound in Medicine and Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing 400016, China
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