Morphine Preconditioning Alleviates Ischemia/Reperfusion-induced Caspase-8-dependent Neuronal Apoptosis Through cPKCγ-NF-κB-cFLIP L Pathway.

BACKGROUND

Perioperative cerebral ischemia/reperfusion injury is a major contributor to postoperative death and cognitive dysfunction in patients. It was reported that morphine preconditioning (MP) can mimic ischemia/hypoxia preconditioning to protect against ischemia/reperfusion injury. However, the mechanism of MP on the ischemia/reperfusion-induced neuronal apoptosis has not been fully clarified.

METHODS

The middle cerebral artery occlusion/reperfusion (MCAO/R) model of mice and the oxygen-glucose deprivation/reoxygenation (OGD/R) model in primary cortical neurons were used to mimic ischemic stroke. In vivo, the infarct size was measured by using TTC staining; NDSS, Longa score system, and beam balance test were performed to evaluate the neurological deficits of mice; the expression of the protein was detected by using a western blot. In vitro, the viability of neurons was determined by using CCK-8 assay; the expression of protein and mRNA were assessed by using western blot, RT-qPCR, and immunofluorescent staining; the level of apoptosis was detected by using TUNEL staining.

RESULTS

MP can improve the neurological functions of mice following MCAO/R ( P <0.001, n=10 per group). MP can decrease the infarct size ( P <0.001, n=10 per group) and the level of cleaved-caspase-3 of mice following MCAO/R ( P <0.01 or 0.001, n=6 p er group). MP can increase the levels of cPKCγ membrane translocation, p-p65, and cFLIP L , and decrease the levels of cleaved-caspase-8, 3 in neurons after OGD/R or MCAO/R 1 d ( P <0.05, 0.01 or 0.001, n=6 per group). In addition, MP could alleviate OGD/R-induced cell apoptosis ( P <0.001, n=6 per group).

CONCLUSION

MP alleviates ischemia/reperfusion-induced Caspase 8-dependent neuronal apoptosis through the cPKCγ-NF-κB-cFLIP L pathway.