[Protective effect of hypoxic preconditioning on SH-SY5Y cells injured by oxygen-glucose deprivation]

To investigate the protection effects of hypoxic preconditioning(HPC) on the SH-SY5Y cell injured by oxygen-glu-cose deprivation(OGD),and to discuss the possible mechanism.

SH-SY5Y cells were randomly divided into 4 groups. In normal group,the cells were cultured without OGD treatment. In HPC group,the cultured SH-SY5Y cells were treated for 5 days by intermittently ex-posing to hypoxic gas mixture (2% O₂,5% CO₂) for 30 min in every day. In OGD group,the culture medium was replaced by glucose-free medium and the cells were transferred to a humidified incubation chamber flushed by a gas mixture of 1% O₂ and 5% CO₂ for 10 h. After that, the cells were fed with glucose-supplemented medium and cultured under normoxic condition for 24 h. In HPC+OGD group,the cultured SH-SY5Y cells were treated for 5 days by intermittently exposing to hypoxic gas mixture for 30 min in each day, then the cells were given the same treatments as those in OGD group. The cell viability was assessed by MTT assay. The degree of the cell damage was evaluated by deter-mining lactate dehydrogenase (LDH) leakage. TUNEL staining were used to detect the variation of cell apoptosis. The expression of Caspase 3 and hypoxia inducible factor-1α(HIF-1α) at protein levels was examined by Western blot.

Hypoxic preconditioning relieved the cells apoptosis,decreased the amount of LDH leakage and improved the viability of SH-SY5Y cells injured by OGD (P<0.05). Western blot showed that the expression of Caspase 3 protein in HPC+OGD group was significantly lower than that in OGD group (P<0.05); HIF-1α protein expression was significantly higher than that of OGD group (P<0.05).

Hypoxic preconditioning has protective effect on in vitro cultured SH-SY5Y cells injured by OGD. The mechanism may be related to the increase of HIF-1a protein.