Pomegranate protective effect on experimental ischemia/reperfusion retinal injury in rats (histological and biochemical study)

Oxidative stress is one mechanism involved in the pathogenesis of ischemia/reperfusion (/R) retinal injury. The histological, biochemical, and functional changes associated with pomegranate (PMG) treatment prior to retinal I/R were analyzed using 40 adult male albino rats. Rats were divided into four groups: Groups I and II (sham operated and received saline or PMG, respectively); Groups III and IV (I/R rat models with prior administration of saline or 250mg/kg/day PMG, respectively). Electroretinogram (ERG) results were recorded and eye specimens were taken and processed for light and electron microscopic examinations and for assessment of oxidative status in retinal homogenate. I/R lead to degenerative changes in retinal layers with a significant reduction in nuclear factor erythroid 2-related factor 2 (Nrf2) immunoreactivity in concomitant with significant oxidant-antioxidant disturbance and decreased a- and b-wave amplitude in the ERG. These alterations were ameliorated with prior PMG treatment. In conclusion, PMG treatment, as an antioxidant, attenuated retinal structural and functional I/R injury through activation of Nrf2 which could be a base for future therapy designs.