Abstract
Purpose: :
To determine outflow facility in a spontaneous and an induced animal model of glaucoma.
Methods: :
9- month old DBA/2J mice (n=3), 3- month old C57BL/6 mice unilaterally injected in the anterior chamber with 10um polystyrene beads for 11 days (n=3) and similarly aged naïve C57BL/6 mice (n=3) were euthanized and their eyes were used for outflow facility measurement. Outflow facility was determined using simultaneous pressure and flow measurements. Flow at constant predetermined levels was achieved with a syringe pump while an inline pressure transducer was used to measure intraocular pressure. Intraocular pressure (IOP) of the microbead injected mice was measured before the polystyrene bead injection and before sacrifice to verify that the injection caused IOP elevation.
Results: :
Uninjected C57BL/6 had outflow facilities ranging between in 0.006 and 0.0084 ul/min/mmHg in all eyes studied. Outflow facility in DBA/2J mice ranged between 0.002 and 0.004 ul/min/mmHg. Intraocular pressure remained elevated in C57BL/6 bead-injected eyes (18.1±4.4mmHg) compared to contralateral eye levels (13.4 ±2.22mmHg). Outflow facilities of bead injected eyes ranged between 0.0024 and 0.0069 ul/min/mmHg. Outflow facilities were significantly different between the three groups (ANOVA, p=0.0014). Post hoc analysis (Tuckey-Kramer test) showed that reduction of outflow facility in DBA as well as bead injected eyes, is statistically significant (p<0.05) compared to control levels.
Conclusions: :
Trabecular meshwork outflow facility in the DBA2/J mouse is markedly decreased at 9 months of age. While the outflow facility is decreased in microbead-injected eyes, this reduction is not as dramatic as that seen in DBA mice.
Keywords: outflow: trabecular meshwork • trabecular meshwork • anterior chamber