The dual cyclooxygenase/5-lipoxygenase inhibitor licofelone attenuates p-glycoprotein-mediated drug resistance in the injured spinal cord.

Abstract There are currently no proven effective treatments that can improve recovery of function in spinal cord injury (SCI) patients. Many therapeutic compounds have shown promise in pre-clinical studies, but clinical trials have been largely unsuccessful. P-glycoprotein (Pgp, Abcb1b) is a drug efflux transporter of the blood–spinal cord barrier that limits spinal cord penetration of blood-borne xenobiotics. Pathological Pgp upregulation in diseases such as cancer causes heightened resistance to a broad variety of therapeutic drugs. Importantly, several drugs that have been evaluated for the treatment of SCI, such as riluzole, are known substrates of Pgp. We therefore examined whether Pgp-mediated pharmacoresistance diminishes delivery of riluzole to the injured spinal cord. Following moderate contusion injury at T10 in male Sprague–Dawley rats, we observed a progressive, spatial spread of increased Pgp expression from 3 days to 10 months post-SCI. Spinal cord uptake of i.p.-delivered riluzole was signi...