A new rat model of glaucoma induced by intracameral injection of silicone oil and electrocoagulation of limbal vessels.

BACKGROUND: A satisfied glaucoma model is absent now. The aim of this study was to evaluate the effect of a combination of intracameral injection of silicone oil and electrocoagulation of corneal limbal vessels and episcleral veins in the rats to establish glaucoma model.

METHODS: Operation was performed in each of the left eyes of 90 adult male rats. Right eyes were used as controls. Measurement of intraocular pressure (IOP) was performed with an applanation tonometer (Tono-Pen). Retinal ganglion cells (RGCs) were retrogradely labeled by applying FluoroGold onto the bilateral superior colliculus.

RESULTS: During the follow-up (24 weeks), the IOP of the study eyes was significantly higher (P < 0.05) than the control eyes (at final examination, IOP of control eyes was (13.4 ± 1.0) mmHg and IOP of study eyes was (16.1 ± 1.8) mmHg). Correspondingly, at 24 weeks after operation, the RGCs density of the study eyes (2286.11 ± 290.45/mm(2)) was significantly lower than the control eyes (2626.46 ± 164.85/mm(2), P < 0.01). In the operated eyes, histological examination showed excavation of optic disc and increased neuroglial cells in the optic nerve, reduced thickness of retina and diminution of retinal ganglion cells, and atrophy of ciliary body and iris. Notably, the anterior chamber angle of the operated eye remained open.

CONCLUSIONS: A combination of intracameral injection of silicone oil and electrocoagulation of corneal limbal vessels and episcleral veins may establish a reliable glaucoma model for further research.