Chronic Ocular Hypertension Induced by Circumlimbal Suture in Rats

Abstract

Circumlimbal suture provides a simple and cost-effective way to induce mild chronic ocular hypertension in rat eyes. This model produces preferential ganglion cell dysfunction and RNFL reduction.

Astrocyte-derived lipoxins A4 and B4 promote neuroprotection from acute and chronic injury

“…To assess whether lipoxin neuroprotective actions extend to chronic neurodegenerative injury, we investigated a rat circumlimbal suture model of glaucoma. In this assay, sustained intraocular pressure (IOP) elevation can be consistently maintained over 15 weeks (32,33), resulting in compromised RGC function, reduced retinal nerve fiber layer (RNFL) thickness, and RGC death (32). As RGC functional deficits are reversible for up to 8 weeks (33), we chose this time point to initiate therapeutic treatment of LXB 4 or vehicle ( Figure 6A).…”

“…injection (1 μg) and topical application to each eye (100 ng). ERG was measured monthly to assess RGC functional changes using the pSTR, as we previously used it to measure the impact of elevated chronic IOP (32,81). In addition, RNFL and total retinal thickness were quantified once a month using OCT. After 15 weeks, animals were euthanized and RGC numbers were counted on central (2000 μm from ON head) and peripheral (4000 μm from ON head) regions of retinal flatmounts following immunofluorescent staining for BRN3a as above.…”

“…A method for reliably inducing sustained IOP elevation in the rodent eye was recently developed by Liu et al (32,77). In this minimally invasive approach, a circumlimbal suture is placed to induce mild chronic ocular hypertension for up to 15 weeks (32).…”

“…A method for reliably inducing sustained IOP elevation in the rodent eye was recently developed by Liu et al (32,77). In this minimally invasive approach, a circumlimbal suture is placed to induce mild chronic ocular hypertension for up to 15 weeks (32). Elevated IOP is the primary clinical glaucoma risk factor, and this model results in similar compromised RGC function, reduced RNFL thickness, and death of RGCs by week 15 (32).…”

“…In this minimally invasive approach, a circumlimbal suture is placed to induce mild chronic ocular hypertension for up to 15 weeks (32). Elevated IOP is the primary clinical glaucoma risk factor, and this model results in similar compromised RGC function, reduced RNFL thickness, and death of RGCs by week 15 (32). Therefore, this model provides an opportunity to assess therapeutic neuroprotective activity in a chronic degenerative environment.…”