The primary hippocampal neural stem cells were cultured and identified by immunofluorescence. The neural stem cells were injured by oxygen and glucose deprivation （OGD） to simulate the HIBD injury in vivo. The cells were divided into control group， OGD group （0 μmol·L^-1 RA intervention） and different concentrations （0.5， 1， 5， 10 and 50 μmol·L^-1） of RA intervention groups. The proliferation activities of cells in various groups were measured by CCK-8 method at 12， 24， 48 and 72 h after OGD. Real-time fluorescence quantitative PCR （RT-qPCR） and Western blotting methods were used to detect the expression levels of retinoic acid receptor alpha（RARα），glycogen synthase kinase-3β（GSK-3β） and CyclinD1 mRNA and the protein expression amounts in the hippocampal neural stem cells in various groups. After different concentrations（0， 0.5， 5.0 and 50.0 μmol·L^－1） of RA intervention， the hippocampal neural stem cells were treated with GSK-3β inhibitor CHIR99021 and divided into control group， 5 μmol·L^－1 RA intervention group， and 0， 0.5， 5.0 and 50.0 μmol·L^－1 RA+20 μmol·L^－1 CHIR99021 intervention groups. The cell proliferation rates were detected by CCK-8 assay at 24 h after OGD. RT-qPCR and Western blotting methods were used to detect the expression levels of RARα， GSK-3β and CyclinD1 mRNA and the protein expression amounts in the hippocampal neural stem cells in various groups.

The immunofluorescence identification results showed that the primary hippocampal neural stem cells were successfully extracted and cultured.The CCK-8 method detection results after RA intervention showed that the proliferation activities of cells in 1.0 and 5.0 μmol·L^－1 RA intervention groups were significantly increased at each time point after OGD compared with OGD group（P<0.05）.Compared with OGD group， the expression levels of RARα，GSK-3β，and CyclinD1 mRNA in 5.0 and 10.0 μmol·L^－1 RA intervention groups were significantly increased （P<0.05），and the expression amounts of RARα and GSK-3β proteins in 1.0，5.0 and 10.0 μmol·L^－1 RA intervention groups were increased.After GSK-3β inhibitor CHIR99021 intervention， compared with 5.0 μmol·L^－1 RA intervention group， the cell proliferation rate in 5.0 μmol·L^－1 RA+20 μmol·L^－1 CHIR99021 intervention group was significantly decreased （P<0.01）， the expression levels of RARα mRNA in 0 and 0.5 μmol·L^－1 RA+20 μmol·L^－1 CHIR99021 intervention groups were significantly decreased （P<0.01），the expression levels of GSK-3β and CyclinD1 mRNA in 0， 0.5， 5.0 and 50.0 μmol·L^－1 RA+20 μmol·L^－1 CHIR99021 intervention groups were significantly decreased （P<0.05），and the expression amounts of GSK-3β and CyclinD1 were decreased.

There is an appropriate concentration window for RA to promote the proliferation of neural stem cells after HIBD injury，and its mechanism may be that RA regulates the transcription of CyclinD1 through the activation of GSK-3β， thus promotes the proliferation of neural stem cells.