advertisement
Abstract #12310 Published in IGR 7-2
Effect of hypercholesterolemia on inducible nitric oxide synthase expression in a rat model of elevated intraocular pressure
Yucel I; Akar Y; Yucel G; Ciftcioglu MA; Keles N; Aslan MVision Research 2005; 45: 1107-1114
See also comment(s) by Daniel Ju •
PURPOSE: This study was performed to examine the effect of hypercholesterolemia on inducible nitric oxide synthase (NOS-2) expression and oxidative tissue injury in an experimental rat model of elevated IOP. METHODS: Wistar rats were maintained on either regular chow or a high-cholesterol diet for 24 weeks. Intraocular pressure (IOP) was elevated in hypercholesterolemic rats by unilaterally cauterizing three episcleral vessels. Rats were divided into four experimental groups as follows; hypercholesterolemia, hypercholesterolemia+elevated IOP, elevated IOP and control. NOS-2 distribution, lipid peroxidation and retinal nerve fiber layer (RNFL) thickness was evaluated in all experimental groups at the end of 24 weeks. RESULTS: Light microscopic evaluation of retinas in hypercholesterolemic rats revealed breaks and discontinuation in focal areas in the outer nuclear layer (ONL). NOS-2 positive staining was observed throughout the outer plexiform layer (OPL), inner plexiform layer (IPL) and ganglion cell layer (GCL) in rats with elevated IOP and/or hypercholesterolemia. Calculated values of RNFL thickness in hypercholesterolemic rats were significantly higher than those in the control and elevated IOP group. Vitreous malondialdehyde (MDA) levels detected in elevated IOP (3.51 ± 0.31 nmol/mg protein) and hypercholesterolemia+elevated IOP (5.14 ± 1.28 nmol/mg protein) groups were significantly higher than those detected in hypercholesterolemic (1.92 ± 1.43 nmol/mg protein) and control (1.89 ± 0.24 nmol/mg protein) groups. CONCLUSION: The presented data confirms hypercholesterolemia as a risk factor in the development of glaucomatous optic neuropathy (GON) and suggests that increased circulating cholesterol may exacerbate disease progression by inducing NOS-2 expression and elevating oxidant tissue injury.
Dr. I Yucel, Department of Ophthalmology, Akdeniz University Medical School, 07070 Antalya, Turkey
Classification:
9.2.2 Other risk factors for glaucoma (Part of: 9 Clinical forms of glaucomas > 9.2 Primary open angle glaucomas)
5 Experimental glaucoma; animal models
9.4.15 Glaucoma in relation to systemic disease (Part of: 9 Clinical forms of glaucomas > 9.4 Glaucomas associated with other ocular and systemic disorders)