ABSTRACT

A preventive strategy against lung ischemia reperfusion injury (LIRI) is pretreatment with certain drugs to make them more resistant to LIRI. The aim of this study was to investigate the preventive effects of everolimus (RAD001) on LIRI in a rat-ventilated ischemia-reperfusion model.

Rats were divided into 8 groups;1 control(I), 6 LIRI (IIa,b,c;IIIa,b,c) and 1 everolimus (IV). LIRI groups underwent 90 min of ischemia and 30 min (IIa-IIIa), 120 min (IIb-IIIb) and 240min (IIc-IIIc) of reperfusion, respectively, and were randomized into two, one without (II) and one with everolimus (III) pretreatment. Groups III received 1mg/kg/day everolimus via oral gavage for 1 week before IR. After reperfusion, bronchoalveolar lavage and lung tissue samples were collected. The mRNA expressions of the samples’ pro-inflammatory genes were determined via qPCR. TNF-α and macrophage inflammatory protein 2 (MIP2) concentrations and caspase-3 activity were measured using ELISA kits. Also, myeloperoxidase (MPO) activity was measured spectrophotometrically.

Everolimus significantly decreased the expression of all study mRNA pro-inflammatory genes for groups IIIb and IIIc(p<0.05). It also decreased MIP2 protein levels in groups IIIb and IIIc, whereas TNF-α protein levels decreased only in group IIIc’s lung tissue samples(p<0.05). A significant downregulation of caspase-3 enzyme activity was detected only in group IIIa(p<0.05).

This study shows that everolimus pretreatment, effectively prevents LIRI by decreasing pro-inflammatory genes’ mRNA expressions, the protein expressions of TNF-α and MIP2, and the activity of caspase 3 and myeloperoxidase.