p38 MAP kinase is responsible for senescence-associated COX-2 expression.

<p>(A) Phosphorylation of p38 MAPK was investigated by Western blot analysis after treatment with IFN-γ and TNF-α, as indicated. (B, C) Expression of the phosphorylated form of p38 MAPK in early- and late-passage hMSCs was determined by immunocytochemistry after treatment with IFN-γ and TNF-α for 30 minutes. (D, E) After treating cells with SB203580, the expression levels of COX-2 and p-p38 were confirmed by Western blot analysis. Cells were treated with IFN-γ and TNF-α for 30 minutes to detect the expression of p-p38 and for 24 hours to detect COX-2 expression. n = 3. (*<i>P</i><0.05).