Abstract
Abstract: :
Purpose: Retinal ganglion cell (RGC) loss occurs in response to increased intraocular pressure (IOP). We investigated the mechanisms of neural cell apoptosis in an effort to develop therapeutic agents aimed at increasing the survival of RGCs in glaucoma. Methods: The intraocular pressures (IOP) in DBA/2J (glaucoma) and C57BL/6 (control) mice at 8 months of age were measured using a micro–electric–mechanical system (FTI–10). The superior colliculus was injected with FluoroGold dye and retrograde labeling of the RGCs was quantitated using whole mount retinas. RGC apoptotic cell death was determined by means of the terminal deoxynucleotidyl transferase–mediated nick end–labeling (TUNEL) assay. Results: The mean IOP ± SD in DBA/2J glaucomatous mice (18.61±3.55 mmHg (male, n=48) and 19.41±1.59 mmHg (female, n=34)) was significantly higher than the mean IOP ± SD in the C57BL/6 control mice (9.38±0.50 mmHg (male, n=26) and 9.39±0.52 mmHg (female, n=26)) (p<0.05). The mean numbers per 509.27×635.76 (µm2) of surviving RGC ± SD in the DBA/2J mice (806±73 (male, n=11) and 687±111 (female, n=7)) were significantly decreased when compared with the mean numbers per 509.27×635.76 (µm2) of surviving RGC in C57BL/6 mice (886±52 (male, n=8) and 960±134 (female, n=6)) (p<0.05). Positive TUNEL staining in RGCs in the DBA/2J mice was observed (10/13), but was not observed in RGCs in C57BL/6 mice (0/16). Conclusions: Retrograde labeling provides a reliable quantitative method for the detection of RGC survival in glaucoma.
Keywords: ganglion cells • intraocular pressure • immunohistochemistry