Neuroprotective effect of epigallocatechin-3-gallate in a mouse model of chronic glaucoma

•Consumption of EGCG plays a neuroprotective role on RGCs in a mouse model of chronic high IOP.•Consumption of EGCG had no effect on the IOP value of mice.•It is the first report studied in ophthalmologic neuroprotective effects of EGCG by oral administration in mice.

Epigallocatechin-3-gallate (EGCG) is a powerful antioxidant with suggested neuroprotective action. This study investigated the protective effects of EGCG against retinal ganglion cells (RGCs) degeneration in an animal model of glaucoma. C57BL/6J mice (n = 54) were divided randomly into four groups: normal control group (group A, n = 12); EGCG control group with EGCG in drinking water (group B, n = 12); microbeads control group with anterior chamber microbeads injection to induce elevation in intraocular pressure (IOP) plus normal drinking water (group C, n = 18); and EGCG study group receiving an anterior chamber microbeads injection plus EGCG in drinking water (group D, n = 12). Animals were treated orally with either vehicle or EGCG (50 mg/kg × d). IOP was measured and animals were sacrificed at days 15 and 27. Neurons were retrograde-labeled by fluorogold and immnunolabeled by class III β-tubulin to quantify RGCs in the retinal ganglion cell layer on flat mounts histologically and compared. All mice that received microbeads injections (groups C and D) developed IOP elevation higher than un-injected control mice. At days 15 and 27, progressive loss of RGCs was observed after microbeads injection in group C (P < 0.01). In contrast, the fluorogold-labeled RGC density and class III β-tubulin-positive RGC density were significantly higher in group D as compared to group C (P < 0.01) but significantly lower than group B (P < 0.01). These parameters did not differ significantly between groups A and B (P > 0.05). The findings suggest the consumption of EGCG plays a neuroprotective role on RGCs in a mouse model of elevated IOP.