Measurement of Aqueous Humor Viscosity in an Experimental Rabbit Model With Corneal Neovascularization

This study investigated the relationship between aqueous humor (AH) viscosity and vascular endothelial growth factor-A (VEGF-A) in a corneal neovascularization (CNV) model.

Ten female New Zealand rabbits were divided into two groups (n = 5 each). CNV was induced by alkaline burns on the right corneas of group B, whereas group A underwent a sham procedure. After 14 days, at least 150 µL of AH was extracted from both eyes. VEGF-A concentration was measured using ELISA, and AH viscosity was determined using a viscometer. Correlations between VEGF-A concentration, total protein concentration, and AH viscosity were assessed.

VEGF-A concentration was significantly elevated in CNV-induced eyes than in noninduced eyes (6029.06 ± 7116.50 pg/mL vs. 115.63 ± 33.19 pg/mL, P < 0.01). Total protein concentration was also elevated in CNV-induced eyes (11.66 ± 9.86 mg/mL) than in noninduced eyes (0.69 ± 0.06 mg/mL, P < 0.01), and correlated positively with VEGF-A (r = 0.84, P < 0.01). AH viscosity was significantly increased in CNV-induced eyes (1.82 ± 1.28 mPa-s) compared to noninduced eyes (1.05 ± 0.01 mPa-s, P < 0.01) and correlated strongly with VEGF-A concentration in CNV-induced eyes (r = 1.00, p = 0.02).

AH viscosity positively correlated with VEGF-A concentration, particularly in CNV-induced eyes with elevated VEGF-A levels.

The correlation between VEGF-A levels and AH viscosity in an experimental model of corneal neovascularization suggests that AH viscosity could serve as a biomarker for predicting IOP or surgical outcomes in conditions like neovascular glaucoma.