Effect of dexmedetomidine on expression of hypoxia-inducible factor-1α during hypoxia/reoxygenation in human renal tubular epithelial cells

Objective To investigate the effect of dexmedetomidine on the expression of hypoxia-inducible factor-1α (HIF-1α) during hypoxia/reoxygenation (H/R) in human renal tubular epithelial cells.Methods Human renal tubular epithelial cells (HK-2 cells) cultured in vitro were randomly divided into 4 groups (n =24 each) using a random number table:control group (group C),dexmedetomidine group (group DEX),H/R group and H/R+ dexmedetomidine group (group H/R + DEX).In group C,the cells were incubated for 28 h in an incubator filled with normoxia at 37 ℃.In group DEX,dexmedetomidine 0.1 nmol/L (final concentration) was added to the culture medium and the cells were incubated for 2 h,and then incubated for 28 h in an incubator filled with normoxia at 37 ℃.In group H/R,the cells were incubated in an anaerobic chamber for 24 h at 37 ℃,and then incubated for 4 h in an incubator filled with normoxia at 37 ℃.In group H/R + DEX,the cells were incubated for 2 h in the culture medium containing dexmedetomidine 0.1 nmol/L (final concentration),incubated in an anaerobic chamber for 24 h at 37 ℃,and then incubated for 4 h in an incubator filled with normoxia at 37 ℃.After treatment in each group,the cell viability was measured by MTT assay,cell apoptosis was measured using flow cytometry,the expression of HIF-1α mRNA was detected using RT-PCR,the expression of HIF-1α and activated caspase-3 protein was detected by Western blot,and the cell growth was observed.The apoptosis rate was calculated.Results Compared with group C,the cell viability was significantly decreased,the apoptosis rate was increased,and the expression of HIF-1α mRNA and protein and activated caspase-3 protein was up-regulated in H/.R and H/R + DEX groups,and no significant change was found in group DEX.Compared with group H/R,the cell viability was significantly increased,the apoptosis rate was decreased,the expression of HIF-1α mRNA and protein was up-regulated,the expression of activated caspase-3 protein was down-regulated,and the cell status was significantly improved in group H/R + DEX.Conclusion The mechanism by which dexmedetomidine attenuates H/ R-induced damage to human renal tubular epithelial cells may be related to up-regulated expression of HIF-1 α and inhibited cell apoptosis. Key words: Dexmedetomidine;  Hypoxia-inducible factor 1, alpha subunit;  Kidney tubules; Epithelial cells;  Reperfusion injury