Celastrol inhibits the inflammatory and NF-kB signaling pathway in the lungs of PAH rats. (A) Quantification of CD68 positive cells per view; (B) Representative immunohistochemistry staining images of CD68 positive cells in lung tissues (×20); (C-F) mRNA expression of MCP-1, IL-1β, IL-6 and IL-10 in the lung tissues. (G) Western blots of IκBα, p-IKKα/β and p-65 in lungs; (H-J) quantification of IκBα, p-IKKα/β and p-65 expression in the lungs. n=8 for each group. *, P<0.05, **, P<0.01, ***, P<0.001. PAH, pulmonary arterial hypertension; MCT, monocrotaline.