Abstract:AIM:To establish an experimental model of high intraocular pressure in mice by laser photocoagulation and to prepare for future research.
METHODS: Experimental model of high intraocular pressure was induced unilaterally in 44 C57BL/6 mice. The fellow eye served as a control. TONO-PEN AVIA Tonomter was used to measure intraocular pressure(IOP)to guarantee IOP value at 1, 2, 4, 8wk. Slit-lamp biomicroscopy was performed throughout the period and the structural changes were assessed histologically. And then, their eyes were enucleated, postfixed, cryoprotected, and embedded in optimal cutting temperature medium. After hematoxylin and eosin stain(HE stain), cryosections of the retina were observed under light microscope. TdT-mediated biotin-dUTP nick end labeling(TUNEL)was performed on the retinal sections to determine apoptosis rate.
RESULTS: IOP of laser-treated eyes was significantly higher than that of control eyes from 1-8wk(P<0.05). The highest IOP was 31mmHg, but only one eye. The IOP was mainly around 20mmHg. In laser-treated eyes, the angle of anterior chamber were narrow. Number of cells in the inner nuclear layer and retial gangllion cell layer was slightly lower than that in control eyes at 2wk, but by 4 and 8wk the number of cells was significantly lower than that in the control contralateral eyes.
CONCLUSION: The laser photocoagulation of limbus causes chronic elevation of IOP and this method may be a promising experimental model for the investigation of biological mechanisms of glaucomatous retinal ganglion cell damage.
