Neuroprotective effect of systemic and/or intravitreal rosuvastatin administration in rat glaucoma model

Aim: To evaluate the neuroprotective effect of rosuvastatin, in a rat experimental glaucoma model. Methods: Ocular hypertension was induced in right eyes of Long-Evans rats (n=30) by cauterization of three episcleral veins. Left eyes were defined as controls. Rats were divided into five groups: oral rosuvastatin, intravitreal rosuvastatin, oral+intravitreal rosuvastatin, intravitreal sham and glaucoma without intervention. Rats were sacrificed at day 14. Retinal ganglion cell (RGC) number was assessed by histopathological analysis. Terminal deoxynucleotidyl transferase-mediated dUTP-nick end-labeling (TUNEL) staining and the expression of glial fibrillary acidic protein (GFAP) in RGC layer was also examined. Results: A significant intraocular pressure (IOP) elevation was seen (P=0.002). Elevated IOP resulted in a significant decrease in number of RGCs in group 5 (70.33±8.2 cells/mm²) when compared with controls (92.50±13.72 cells/mm²; P=0.03). The RGC number in group 1 (92.4±7.3 cells/mm²) was significantly higher than group 5 (P=0.03). The numbers of RGC in groups 2, 3 (57.3±8.2 cells/mm², 60.5±12.9 cells/mm²) were comparable with that of group 5 (P=0.18 and P=0.31). The apoptosis rates with TUNEL staining were also parallel to RGC number. Animals with experimentally induced glaucoma showed an increase in retinal GFAP immunoreactivity. Conclusion: Decrease in RGC loss and apoptosis suggest the neuroprotective potential of oral rosuvastatin treatment in a rat model of ocular hypertension. However intravitreal rosuvastatin showed a contrary effect and further studies are required.