Abstract
Purpose::
Recent evidence supports a role for oxidative injury in the pathogenesis of retinal degenerations. Para-aminobenzoic acid (PABA) is a cyclic amino acid belonging to the Vitamin B group which may act to decrease oxidative injury and lipid peroxidation. Our aim was to evaluate the efficacy of PABA in slowing retinal degeneration in the rd10 mouse model of retinal degeneration.
Methods::
PABA (50mg/kg) was administered intraperitoneally six times per week in 15 rd10 mice from post-natal day 3. Ten control rd10 mice were similarly injected with saline. At 3 and 4.5 weeks of age, electrophysiological (full field electroretinogram - ERG) and quantitative histological techniques were used to assess the course and extent of retinal degeneration.
Results::
Dark adapted mixed rod-cone ERG responses were 25-30% higher in PABA-treated rd10 mice as compared with saline-injected animals at both the 3 and 4.5 week time points. At 4.5 weeks, thickness of the outer nuclear layer (ONL) was better preserved in the peripheral retina of PABA-treated mice as compared with saline-injected controls (10.5±1µm versus 8.2±0.8µm, Mean±SEM, p<0.05, t-test). A trend towards a thicker ONL in the central and mid-peripheral retina was also observed in PABA-treated mice.
Conclusions::
PABA treatment may slow the course of retinal degeneration in rd10 mice. Whether this rescue effect is mediated by the anti-oxidant properties of PABA is currently being evaluated.
Keywords: antioxidants • oxidation/oxidative or free radical damage • retinal degenerations: hereditary