Objective:To investigate whether all-trans retinoic acid(ATRA)can inhibit apoptosis effects on primary neurons caused by oxygen and glucose-deprivation(OGD). Methods:Primary neurons were isolated and cultured in vitro

and were determined for neuron-specific enolase(NSE) by immunofluorescence technique. Primary neurons were divided into three groups:control group

OGD group and OGD+ATRA group. Cell morphology before and after OGD injury was observed by inverted microscopy. Apoptosis rate of primary neurons after OGD injury was measured by flow cytometry. The gene transcription levels of retinoic acid receptor alpha(RARα)

transforming growth factor-β1(TGF-β1)

transforming growth factor-β2(TGF-β2)

cysteinyl aspartate specific proteinase(Caspase-3)were examined via real-time PCR

while the protein expressions of RARα

TGF-β

Caspase-3 were determined by Western blot. Results:Successfully cultured primary neurons

neuron-specific enolase was observed in primary neurons obviously. After OGD injury

the cell death of OGD group was more obvious than OGD+ATRA group. Flow cytometry suggested that the apoptosis rate of OGD+ATRA group(26.11±2.96)% significantly decreased when compared with that of OGD group(52.14±5.23)%(P=0.025). The m RNA and protein levels of RARα in OGD+ATRA group(1.52±0.43

0.22±0.02)were significantly higher than those in OGD group(0.49±013

0.10±0.02)(P=0.006

P=0.005). The m RNA transcription levels of TGF-β1

TGF-β2 were significantly lower in OGD+ATRA group(0.45±0.10

0.41±0.08)than in OGD group(0.81±0.15

0.98±0.15)(P=0.034

P=0.018). The protein expressions of TGF-β

Caspase-3 were significantly lower in OGD+ATRA group(0.22±0.04

0.18±0.03)than in OGD group(0.39±0.05

0.47±0.06)(P=0.016

P=0.002). And the m RNA transcription of Caspase-3 in OGD +ATRA group(1.08 ±0.49) and OGD group(1.00 ±0.15) were not significantly different(P =0.148).Conclusion:ATRA inhibits the apoptosis of primary neurons induced by OGD injury via activating its receptor RARα and then turning down TGF-β and Caspase-3 expressions.