Corneal Protein Nitration in Experimental Uveitis

Abstract

Increased expression of inducible nitric oxide synthase (NOS-2) in inflammatory diseases like uveitis suggests that it contributes to the observed pathological state. The aim of this study was to evaluate corneal expression of NOS-2 and corneal protein nitration in a rat model of uveitis. A single injection of intravitreal lipopolysaccharide was used to induce uveitis. Corneal proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and visualized by Coomassie blue staining. Expression of NOS-2 and nitrotyrosine (NO(2)Tyr) formation were determined via immunohistochemistry and Western blot analysis. Total nitrate/nitrite levels in the vitreous were measured by spectral analysis via the Griess reagent. Immunohistochemical analysis revealed increased corneal NOS-2 and NO(2)Tyr immunoreactivity in rats with uveitis compared with controls. NOS-2 and NO(2)Tyr immunoreactivity was observed in and around basal cells in the corneal epithelium. Western blot analysis of corneal lysates showed multiple nitrated protein bands in uveitic rats. Spectrophotometric measurement of total nitrate/nitrite levels in the vitreous affirmed significantly increased levels of nitric oxide generation in uveitis (126 +/-2.63 microM/mg protein) compared with controls (65 +/-6.57 microM/mg protein). The presented data suggests that extensive formation of protein nitration and reactive nitrogen species in the cornea contributes to tissue destruction in uveitis. Hence, selective inhibition of NOS-2 may prevent long-term complications and lead to an improvement in the management of uveitis.

Inhibition of neutral sphingomyelinase decreases elevated levels of nitrative and oxidative stress markers in liver ischemia–reperfusion injury

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Effect of astaxanthin on hepatocellular injury following ischemia/reperfusion

“…Peroxidase staining was performed as previously described (Aslan et al, 2007). Briefly, sections were deparaffined, rehydrated and washed with Tris buffered saline.…”

Manganese porphyrin reduces retinal injury induced by ocular hypertension in rats

“…In animal models of ocular hypertension, elevated IOP augments apoptosis in retinal cells (Aslan et al, 2006) suggesting that nitrative stress exacerbates disease progression in clinical conditions accompanied by ocular degeneration (Aslan et al, 2007; Yücel et al, 2006). Nitric oxide-mediated cytotoxicity and the capacity of NO to induce apoptosis have been documented in macrophages (Sarih et al, 1993), astrocytes (Hu and Van Eldik, 1996), and neuronal cells (Heneka et al, 1998).…”