OBJECTIVETo explore the role of P38 signaling pathway in neonatal rat astrocyte swelling and the expression of aquaporin-4 (AQP4) after oxygen-glucose deprivation (OGD) and recovery (OGD/R).

METHODSPrimarily cultured neonatal rat astrocytes were subject to OGD for 5 h followed by oxygen-glucose recovery in the presence or absence of the P38 inhibitor SB203580 (10 µmol/L). The astrocytes were investigated at 0.5, 2, 8 and 24 h after oxygen-glucose recovery for morphological changes and cell injuries using lactate dehydrogenase (LDH) assay. The expressions of P38, P-P38, and AQP4 mRNAs and proteins in the astrocytes were detected using RT-PCR and Western blotting.

RESULTSOGD/R caused significantly enhanced expression of P-P38 protein, and this effect was blocked by SB203580. AQP4 mRNA and protein expression declined transiently at 0.5 h after OGD and increased gradually to reach the peak level at 8 h (P<0.05). Application of the SB203580 significantly lowered OGD-induced AQP4 mRNA and protein up-regulation (P<0.05). Astrocyte swelling occurred after OGD/R but was obviously lessened by SB203580. LDH release increased markedly after OGD/R, and was attenuated by treatment with SB203580 (P<0.01).

CONCLUSIONP38 signaling pathway participates in astrocyte swelling after OGD/R, and blocking this pathway can attenuate AQP4 up-regulation and ameliorate the cell swelling.