Dexmedetomidine protects H9c2 cardiomyocytes against oxygen-glucose deprivation/reoxygenation-induced intracellular calcium overload and apoptosis through regulating FKBP12.6/RyR2 signaling

摘要

Purpose: Intracellular calcium ([Casup2+,/sup]i) overload is a major cause of cell injury during myocardial ischemia/reperfusion (I/R). Dexmedetomidine (DEX) has been shown to exert anti-in?ammatory and organ protective effects. This study aimed to investigate whether pretreatment with DEX could protect H9c2 cardiomyocytes against oxygen-glucose deprivation/reoxygenation (OGD/R) injury through regulating the Casup2+,/sup signaling. Methods: H9c2 cardiomyocytes were subjected to OGD for 12?h, followed by 3?h of reoxygenation. DEX was administered 1?h prior to OGD/R. Cell viability, lactate dehydrogenase (LDH) release, level of [Casup2+,/sup]i, cell apoptosis, and the expression of 12.6-kd FK506-binding protein/ryanodine receptor 2 (FKBP12.6/RyR2) and caspase-3 were assessed. Results: Cells exposed to OGD/R had decreased cell viability, increased LDH release, elevated [Casup2+,/sup]i level and apoptosis rate, down-regulated expression of FKBP12.6, and up-regulated expression of phosphorylated-Ser2814-RyR2 and cleaved caspase-3. Pretreatment with DEX significantly blocked the above-mentioned changes, alleviating the OGD/R-induced injury in H9c2 cells. Moreover, knockdown of FKBP12.6 by small interfering RNA abolished the protective effects of DEX. Conclusion: This study indicates that DEX pretreatment protects the cardiomyocytes against OGD/R-induced injury by inhibiting [Casup2+,/sup]i overload and cell apoptosis via regulating the FKBP12.6/RyR2 signaling. DEX may be used for preventing cardiac I/R injury in the clinical settings.