Edaravone attenuates lung injury in a hind limb ischemia-reperfusion rat model: A histological, immunohistochemical and biochemical study.

Edaravone is a potent free radical scavenger that has a promising role in combating many acute lung injuries. Ischemia/reperfusion process is a serious condition that may lead to multiple organ dysfunctions. This work was designed to investigate novel mechanisms underlying ischemia/reperfusion-induced lung injury and to evaluate the protective role of edaravone. Thirty adult male rats were divided into three experimental groups; operated with no ischemia (Sham-group), ischemia/reperfusion (I/R) group and edaravone-I/R group. Hind limb ischemia was carried out by clamping the femoral artery. After two hours of ischemia for the hind limb, the rat underwent 24h of reperfusion. Rats in the edaravone-I/R group received edaravone (3mg/kg), 30min before induction of ischemia. At the end of the I/R trial, specimens from the lungs were processed for histological, immunohistochemical, enzyme assay, and RT-qPCR studies. Specimens from I/R group showed focal disruption of the alveolar architecture. Extensive mononuclear cellular infiltration particularly with neutrophils and dilated congested blood capillaries were observed. A significant increase in iNOS, NF-κB, and COX-2 immunoreaction was detected and confirmed by RT-qPCR. Ultrastructural examination showed RBCs and fluid inside alveoli, cellular infiltration, and vacuolations of the inter-alveolar septum. In addition to the presence of extravasated neutrophils and RBCs within the inter-alveolar septum. In contrast, minimal changes were observed in rats which received edaravone before the onset of the ischemia. It could be concluded that edaravone exerted a potent protective effect against lung injury induced by a hind limb I/R in rats through its antioxidant and anti-inflammatory activities.