Protective effect of dexmedetomidine preconditioning on H9C2 cells hypoxia/reoxygenation injury

Objective To explore the anti-inflammatory effect of dexmedetomidine(Dex) in attenuating hypoxia/reoxgenation(H/R) injury of H9C2 cells. Methods Rat cardiomyocyte cell line H9C2 cells were cultured in vitro, and Na2S2O4 was used to establish the hypoxia and reoxygenation injury model on H9C2 cells. Cultured H9C2 cells were divided into three groups: normal control group (group C), the cells were cultured as usual, group H/R, the cells were subjected to 1 h hypoxia induced by 4 mmol/L Na2S2O4, then followed by 12 h reoxygenation by replaced the normal media, Dex preconditioning group (group D), Dex at various concentrations(0.1, 1.0, 10.0 μmol/L) was performed prior to Na2S2O4-induced H/R injury, the rest of the steps are essentially the same as the group H/R. The cell survival rate 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyltetrazolium bromide(MTT) and lactate dehydrogenase(LDH) activity were detected after treatment, the cellular morphology was observed by inverted miscroscope, the TNF-α, IL-6, IL-1β mRNA expression were detected by reverse transcription-polymerase chain reaction(RT-PCR). Results Compared with the group C, the cell survival of group H/R decreased to(44±12)%(P<0.01), LDH activity increased significantly(P<0.01), compared with the group H/R, the cell survival rate and LDH activity of the group D were improved, Dex at 1 μmol/L concentration preconditioning significantly restored cell viability to(75±7)%(P<0.05) and reduced the activity of LDH significantly(P<0.05). The condition of cell necrosis, irregular cell arrangement, and the decline of cell membrane refractive index caused by H/R injury were partly reversed by Dex. Compared with the group C, the TNF-α, IL-6, IL-1β mRNA expression level of the group D and the group H/R increased significantly. Compared with group H/R, the TNF-α, IL-6, IL-1β mRNA expression levels of group D decreased significantly(P<0.05). Conclusions Dex preconditioning attenuates hypoxia and reoxygenation injury of H9C2 cells. The mechanism may be related to inhibiting inflammatory reaction. Key words: Dexmedetomidine; Proconditioning; Hypoxia/reoxygenation injury; Inflammatory response