The evaluation of neuroprotective effect of systemic and/or intravitreal rosuvastatin administration in rat glaucoma model

Purpose: The purpose of the study was to evaluate the neuroprotective effect of rosuvastatin, in a rat experimental glaucoma model.Methods: Chronic ocular hypertension was induced in right eyes of Long Evans rats (n=60) by cauterization of three episcleral veins. Left eyes were defined as control group. Rats were divided into five groups; group 1 (1mg/kg/day oral rosuvastatin), group 2 (intravitreal rosuvastatin), group 3 (oral+intravitreal rosuvastatin), grup 4 (intravitreal sham) and group 5 (only glaucoma model). Animals were examined for changes in IOP by a TonoPen(Medtronic Solan, FL, USA). Rats were sacrificed at day 14. Total cell number was assessed by histopathological analysis. Terminal deoxynucleotidyl transferase-mediated dUTP-nick end-labeling (TUNEL) staining was performed and the expression of glial fibrillary acidic protein (GFAP) was examined to evaluate changes of retinal ganglion cell (RGC) apoptosis and glial cell activation.Results: A significant IOP elevation was seen as early as one day, and maintained for up to 2 weeks, after surgery (p<0.0001). Elevated IOP resulted in a significant decrease in number of RGCs in group 5 (70.33±8.2 cells) when compared with control eyes (94.8±9.7 cells; p=0.03). The number of RGC in group 1 (92,4±7,3 cells) was significantly higher than group 5 (p=0.03). The number of RGC in group 2 (57,3±8,2 cells) and group 3 (60,5±12,9 cells) was significantly reduced compared with group 5 (p=0,004 and p=0.261 respectively). The apoptosis rates with TUNEL staining were parellel to RGC number (0.9%, 10.4%, 3.3%, 0.0% and 5.6% respectively). GFAP expression and TUNEL staining revealed significant decreases in RGC apoptosis and glial cell activation after oral rosuvastatin administration.Conclusion: Decrease in RGC loss and apoptosis suggest the neuroprotective potential of oral rosuvastatin in an animal model of chronic ocular hypertension, but further studies are required.Key words: Rat glaucoma model, rosuvastatin, neuroprotection