Desflurane Via PI3-K/Akt Kinase Signal Pathways Regulates HO-1mRNA Expression and Protects Neuron Against Oxygen-glucose Deprivation

Objective To investigate the signal pathway of HO-1 expression in desflurane-induced after neuronischemia-reperfusion,and explore neuroprotection mechanisms of desflurane.Methods Newborn(24～48 h)Wistar rats were decapitated and hippocampus tissue was dissected.Then digestion with 0.125% trypsin,and suspended in a medium containing DMEM supplemented to 25 mmol/L glucose,10% fetal bovine serum,10% horse serum,and 2 mmol/L glutamine.Cells were cultured at 1.0 ×105 /mL on poly-dlysine-treated 96-well(100 μL/well)plates as well 6-well(2 mL/well)plates.Cultures were treated with 10 μmoL/L cytosine arabinoside on day 4 in culture to minimize glial growth.One-half of the medium was replaced twice a week.Cells were used after culture 7 days.For ischemia-reperfusion(oxygen glucose deprivation,OGD)experiments,cultures were washed three times in a glucose-free balanced salt solution(BSS).They were then placed in deoxygenated glucose-free medium and sealed under 95% N2-5% CO2 in an anaerobic chamber equilibrated to 37 ℃ and 100% humidity for 45 min.OGD was terminated by replacement of stored medium and by returning the cultures to a standard incubator maintained at 37 ℃in 21% O2-5% CO2.Experimental group cells were respectively carried out OGD(group I/R),OGD+6% Desflurane(group Des),OGD+6% Desflurane +10 μmoL/L tin-protoporphyrin(group Tin),OGD+6% Desflurane +10 μmol/L LY 294002(group LY),OGD+6% Desflurane +10 μmol/L Triciribin(group Tri).Control cells were cultured normally.Group Des was carried out OGD meanwhile anesthesized with 6% Desflurane.Group Tin,LY and Tri cells was carried out OGD meanwhile culture medium was added 10 μmoL/L tin-protoporphyrin,10 μmoL/L LY294002 or 10 μmoL/L Triciribin respectivly,and anesthesized with 6% Desflurane.Compound remained present throughout the duration of the experiment until analysis 24 h later.Neuron viability and apoptosis were measured.The expression of HO-1mRNA,PI3-K and Akt protein were detected.Results Desflurane enhanced expression of HO-1mRNA,PI3-K and Akt,meanwhile increased neuron viability and decreased neuron apoptosis(vs group I/R,P0.01).Tin-protoporphyrin inhibited HO-1-mRNA,as well increased neuron apoptosis and decreased neuron viability(vs group Des,P 0.01).LY 294002 inhibited PI3-K,Akt and HO-1mRNA,increased neuron apoptosis and decreased neuron viability(vs group Des,P0.05 or P0.01).Triciribin inhibited Akt and HO-1-mRNA,increased neuron apoptosis and decreased neuron viability(vs group Des,P0.01).Conclusion Desflurane via PI3-K/Akt cell-survival signaling pathways regulates hemeoxygenase-1 and protects neuron against ischemia-reperfusion injury.