Changes in Retinal Neuronal Population in DBA/2J Mice with Topical Intraocular Pressure Lowering Drugs

PURPOSE: The DBA/2J (D2) mouse is a transgenic mouse with pigmentary glaucoma. In a previous study, we found a reduction of inner retinal thickness in D2 mice. We attempted to discover the effect of eye drops on the retina of D2 mice. METHODS: Ten-month-old D2 mouse eyes were treated with Timoptic XE(R), Cosopt(R), and Xalacom(R) eye drops for a 1-month period. Immunohistochemical staining was performed on the mouse eye sections for analysis. RESULTS: In the control group, GABA and OPN immunoreactivity were markedly decreased and NOS immunoreactivity was increased. In all experimental group, GABA and OPN immunoreactivity were increased, and OPN immunoreactivity was markedly increased especially in the Cosopt(R) group. NOS immunoreactivity was decreased in all experimental groups. There was no difference in glycine immunoreactivity between the control and experimental groups. CONCLUSIONS: Combination anti-glaucoma eye-drops to the D2 mouse changed the retinal neuronal population and these drugs might play an important role in the mechanisms of retinal neuronal death; potential strategies for neuroprotection should therefore be evaluated.

Histologic Characteristics in the Eyes of DBA/2J Mice according to the Degree of Intraocular Pressure

PURPOSE: We assessed the correlation between ocular abnormalities and the degree of intraocular pressure (IOP) in the DBA/2J (D2) transgenic mice which were proven to have pigmentary dispersion syndrome and developing glaucoma. METHODS: Nine-months-old D2 mice were examined with biomicroscopy under anesthesia and measured for IOP by Tono-Pen, Hematoxylin and eosin staining was performed on the eye sections of the mice to analyze differences between the low-grade IOP group and the high-grade IOP group. RESULTS: Ocular abnormalities including iris pigment loss, iris transillumination, iris stromal atrophy, anterior synechia, thinning of the retina, and ganglion cell loss were found; all of which appeared to be pressure- dependent. CONCLUSIONS: These results corroborate that both IOP and age might be considered for studies using D2 mice, and suggest that D2 mice are a useful glaucoma model to study the mechanisms of retinal ganglion cell death and to evaluate strategies for neuroprotection.