A novel imidazopyridine derivative, X22, prevents the retinal ischemia-reperfusion injury via inhibition of MAPKs

Inflammation is a pathological hallmark of ischemia reperfusion (I/R) injury. The present study was conducted to explore the ability of a new anti-inflammatory compound, X22, to attenuate retinal I/R injury via cytokine-inhibitory mechanism. For the in vitro experiment, ARPE-19 cells were pretreated with X22 (5 or 10 μM) or saline for 2 h, followed by stimulation with tert-butyl hydroperoxide (TBHP, 1000 μM) for an indicated amount of time. The expression of inflammatory mediators , cell viability , and cell apoptosis were evaluated. For the in vivo experiment, the rats were randomized to receive treatment with saline or X22 (0.1 μM/kg, 3 μL) before the induction of I/R injury. Histological evaluation, apoptosis of retinal cells, macrophage infiltration, and retina functional changes were further determined. Our data showed that pretreatment with X22 significantly inhibited TBHP-induced inflammatory cytokine expression in ARPE-19 cells. The anti-inflammatory activity of X22 may be associated with its inhibition on MAPKs, rather than NF-κB. Subsequently, our data proved that TBHP induced apoptosis in ARPE-19 cells, while pretreatment of X22 significantly suppressed TBHP-caused ARPE-19 apoptosis. Finally, the in vivo data revealed that X22 administration maintained better inner retinal layer structures, reduced apoptosis of retinal ganglion cell, and improved retinal function in retinal I/R rat models, which were accompanied with a remarkable decrease in retinal macrophage infiltration. These results suggest that the novel compound X22 is a potential agent for the treatment of retinal I/R-related diseases via the MAPKs-targeting anti-inflammatory mechanism and deserves the further development.