Protocol for Conditional Knockout Mouse Model of OHT and Glaucoma

This chapter describes the protocols used to create a conditional knockout mouse model to study partially closed-angle glaucoma where the intraocular pressure (IOP) is raised beyond normal levels. The Cre/loxP approach was employed as a strategy to conditionally inactivate the AP-2β gene from the developing periocular mesenchyme (POM) that is responsible for creating the trabecular meshwork (TM) (Taiyab et al., 2022). The Mgp-Cre knock-in (Mgp-Cre.KI) mice, in combination with the AP-2β floxed mice, were utilized to create a targeted deletion of AP-2β to the TM area. The AP-2β TMR KO mutants exhibit an absent TM and underdeveloped Schlemm’s canal (SC) and partial adherence of the iris to the cornea. The mutants have significantly higher IOP than their wild-type littermates by one month of age, and this is correlated with a progressive, significant loss of retinal ganglion cells, reduced retinal thickness, and reduced retinal function, as measured by electroretinography. Thus, these mutant mice can serve as a model for understanding and treating progressive human primary angle-closure glaucoma with associated ocular hypertension.