Doxycycline HClS4005

Doxycycline (50 μM) completely inhibits degradation of type II collagen, but not that of type I collagen in rheumatoid synovial fibroblasts and endothelial cells. Doxycycline (50 μM) down-regulated MMP-8 induction, at both the mRNA and protein levels in rheumatoid synovial fibroblasts and endothelial cells. ^[1] Doxycycline not only inhibits MMP-8 and MMP-9 (gelatinase B) activity, but also the synthesis of MMPs in human endothelial cells. Doxycycline (50 μM) completely inhibits the phorbol-12-myristate-13-acetate (PMA)-mediated induction of MMP-8 and MMP-9, as measured by Western blotting and gelatin zymography, respectively. ^[2] Doxycycline inhibits the LPS-induced IL-1beta increase in the mRNA and protein amounts in the corneal epithelium and upregulates the expression of the anti-inflammatory IL-1 RA protein in human cultured corneal epithelium. Doxycycline reduces the steady state level of the cellular ICE protein but does not affect the level of ICE transcripts. Doxycycline significantly decreases IL-1beta bioactivity in the supernatants from LPS-treated corneal epithelial cultures