tcsc2890 Doxycycline (hyclate)

Doxycycline (hyclate) is a tetracycline antibiotic and broad-spectrum metalloproteinase (MMP) inhibitor.

In Vitro: Doxycycline shows excellent effectiveness and time-dependent characteristics against M. gallisepticum strain S6 in vitro^[2]. Osteoblasts exposed to the composite containing 25 μg/mL doxycycline (DOX)/β-cyclodextrin (βCD) has increased cell proliferation (p < 0.05) compared to control osteoblast cultures at all experimental time points, reaching a maximum in the second week. Alkaline phosphatase (AP) activity and collagen secretion levels are also elevated in osteoblasts exposed to the DOX/βCD composite (p < 0.05 vs. controls) and reach a maximum after 14 days^[3]. Doxycycline (20 nM) inhibits ECM (extracellular matrix) production and remodeling in both SMC (smooth muscle cell) types of cultures, and synthesis of collagens and isoprenylated proteins in SMC-Ch (a cholesterol-rich diet) is a higher than in SMC-C (a standard diet)^[4].

In Vivo: In heterozygous (HT) Col3a1 knockout mice, after 3 months of treatment with doxycycline or placebo, 9-month-old HT or wild-type (WT) mice are subjected to surgical stressing of the aorta. A 3-fold increase in stress-induced aortic lesions found in untreated HT mice 1 week after intervention (cumulative score 4.5±0.87 versus 1.3±0.34 in WT, p<0.001) is fully prevented in the doxycycline (25 or 100 mg/kg, p.o.)-treated group (1.1±0.56)^[1].