PD98059 Protects Cerebral Cortex Mitochondrial Structure and Function at 48 h Post-Resuscitation in a Rat Model of Cardiac Arrest

Background: Mitochondria play a critical role as effectors and targets of brain injury in the post-resuscitation period. Although we found previously that the extracellular signal-regulated kinase (ERK)1/2 inhibitor PD98059 (PD) protects the brain against mitochondrial-mediated cell death at 24 h post-resuscitation in rats subjected to cardiac arrest/cardiopulmonary resuscitation (CA/CPR), it is not clear whether PD also exerts mitochondrial protective effect for a lasting time. Therefore, we examined the effect of PD on brain mitochondria at 48 h post-resuscitation to evaluate the time-effect of PD in the current study. Methods: Experimental rats were divided randomly into 5 groups: Sham, CA, dimethylsulfoxide (DMSO), 0.15mg/kg PD and 0.3mg/kg PD. Rats except for sham group were subjected to CA for 6 min followed by CPR. We detected survival rates and neurologic deficit scores, cerebral cortex mitochondrial function by evaluating adenosine triphosphate (ATP) levels, mitochondrial permeability transition pore (MPTP) opening, and the expression of mitofusin2 (Mfn2) and observing the ultrastructure by electron microscopy at 48 h post-resuscitation in a 6-min CA rat model. Results: PD improved survival rates and neurologic deficit scores, alleviated cerebral cortex mitochondrial damage by reducing MPTP opening and increasing Mfn2 production at 48 h post-resuscitation in a 6-min CA rat model. Conclusion: A single dose of PD improved 48 h post-resuscitation outcome and mitochondrial function, indicating the potential of the use of ERK inhibitors for the treatment of brain injury resulting from CA in the future.