Reduced retinal ganglion cell dendrite integrity followed by retinal nerve fiber layer thinning in a laser-induced monkey ocular hypertension model.

PURPOSE: To evaluate time-dependent changes in retinal ganglion cell (RGC) dendrites and soma, as well as other retinal structural alterations, in a monkey ocular hypertension (OHT) model for preclinical glaucoma research.

METHODS

Elevated intraocular pressure (IOP) was induced by laser application in monkey eyes. Changes in retinal nerve fiber layer (RNFL) thickness, ganglion cell-inner plexiform layer (GCIPL) thickness, RGC count and the microtubule-associated protein 2 (MAP2)-positive signal in the inner plexiform layer (IPL) were evaluated at 4, 6 and 8 weeks after laser application.

RESULTS

IOP elevation was sustained in monkey laser-treated eyes throughout the study period. Reduction of GCIPL thickness followed by RNFL thinning was observed in the macular region. RGC count and MAP2+ signal in IPL were significantly decreased in laser-treated eyes in consistent to GCIPL thinning.

CONCLUSIONS

This study revealed the temporal alterations not only in RGC axons but also in dendrites and cell bodies, and their relationships in the monkey OHT model. This highlights the importance of assessing RGC dendrites, which are closely linked to RGC function, rather than focusing solely on the survival of RGC soma or preservation of RNFL thickness when testing novel neuroprotective agents.