Upregulation of glutamate metabolism by BYHWD in cultured astrocytes following oxygen‑glucose deprivation/reoxygenation in part depends on the activation of p38 MAPK

Recent studies have demonstrated that Buyang Huanwu Decoction (BYHWD) decreased glutamate levels subsequent to cerebral ischemia. Glutamate transporter‑1 (GLT‑1) and glutamine synthetase (GS), which are located in astrocytes, mainly contribute to glutamate transportation, thus reducing glutamate concentration. BYHWD has previously been demonstrated to upregulate GLT‑1 and GS following ischemia in vivo. However, whether BYHWD can directly influence astrocytic GLT‑1/GS levels remains unknown. In the present study, the effect of BYHWD containing serum (BYHWD‑CS) on GLT‑1/GS levels in astrocytes following oxygen‑glucose deprivation/reoxygenation (OGD/R) was investigated. The results revealed that BYHWD‑CS enhanced the expression levels of GLT‑1 and GS in cultured astrocytes, which reduced glutamate concentration in the culture medium. Meanwhile, increased p38 mitogen‑activated protein kinase (p38 MAPK) was phosphorylated (activation form) by BYHWD‑CS in cultured astrocytes, and the specific p38 inhibitor SB203580 blocked the increase of GLT‑1/GS accompanied by decreased cell viability. Furthermore, SB203580 suppressed the effect of BYHWD‑CS on the level of glial fibrillary acidic protein (an astrocytic marker), thus confirming that astrocytes are directly involved in the protective role of BYHWD after OGD/R. These findings suggest that BYHWD upregulates GLT‑1 and GS via p38 MAPK activation, and protects cultured astrocytes from death caused by OGD/R (typical in vitro model), which complemented the role of astrocytes in the protective effect of BYHWD.