Abstract
Purpose :
Chronic electrical stimulation might inhibit the growth of angiogenesis [Y. Inoue et al., 2018]. To investigate the inhibitory effect of transcorneal electrical stimulation (TES) on the progression of early choroidal neovascularization (CNV), we measured and compared CNV volumes, with and without TES in rat CNV models and evaluated this hypothesis.
Methods :
CNVs were induced using a photocoagulation laser device in both eyes of 15 Brown Norway rats. A 4 mA, 60 kHz sinusoidal current was applied to the cornea through a conductive gel (2% agarose) for 30 min/day for 7 days in one eye on the day after beginning laser irradiation. Eight days after laser irradiation, fluorescein angiography (FA) was performed to observe the CNV status. Then, the CNV was observed after the choroid-sclera specimen was stained with GSL I-B4 isolectin (DL-1207, Vector Laboratories). The volume of the CNV was calculated by combining images taken with a confocal laser microscope (C2, Nikon) at a 1 um pitch along the Z-axis from the CNV apex to the sclera side. All the experiments were conducted in accordance with the approval of the institutional Animal Care and Use Committee of Nidek Co., Ltd.
Results :
CNV lesions were observed at the laser-irradiated location from the hyperfluorescence in the second half of FA (Fig. 1). CNVs showed strong red fluorescence when viewed under a confocal laser microscope with a 561 nm light source (Fig. 1). The CNV volumes are shown in Figure 2. The CNV volume of electrically stimulated eyes (827,513 ± 341,693 μm3, CNV; n = 40, Mean ± SD) was significantly smaller (p 0.05, independent t-test) compared to the CNV volume of control eyes without electrical stimulation (1,108,831 ± 349,279 μm3, CNV; n = 32). No rat suffered corneal opacity or other injuries due to TES.
Conclusions :
The results of this study suggest that TES can inhibit the progression of early CNV. We will investigate more effective stimulation conditions in the future studies.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.