Effect of hypoxic preconditioning on sphingosine kinase-1 expression and blood-brain barrier permeability in rats after traumatic brain injury / 中华神经医学杂志

ABSTRACT

Objective To explore the effect ofhypoxic preconditioning (HPC) on the expression of sphingosine kinase-1 (SphK-1) and blood-brain barrier (BBB) permeability in rats after traumatic brain injury (TBI).Methods Two hundred and four SD rats were randomly assigned into TBI group (n=96),HPC group (giving HPC and TBI,n=96) and blank control group (n=12).The rats in the TBI group were subjected to TBI with freefall impact method,while the rats of HPC group were treated with the same methods after HPC (50.47 kpa,3 d,3 h/d).And then,they were sacrificed at each time point (1,4,8 and 12 h,and 1,3,7 and 14 d after injury).RT-PCR and Western blotting were employed to detect the mRNA and protein expression changes of SphK-1 in brain contusion area at each time points after injury.Immumohistochemical staining (IgG method) was used to detect the BBB permeability changes of the rats.Results IgG scores and Sphk-1 mRNA and protein expressions in rats of TBI group and HPC group began to increase at 1 h after injury and reached the highest level 1 d after injury; they were still higher than the normal levels,with significant differences (P＜0.05); SphK-1 mRNA and protein expressions in all the three groups had the same increased trend at all the time points excepted on the 14th d of injury,with significant differences (P＜0.05).IgG scores showed that the BBB permeability in the TBI group at each time point was significantly higher than that in the HPC group (P＜0.05).Conclusion Hypoxic preconditioning can increase SphK-1 expressions after TBI to promote sphingosine 1-phosphate sphingosine transformation so as to protect of the integrity of BBB.