doxycycline versus curcumin for inhibition of matrix metalloproteinase expression and activity following chemically induced inflammation in corneal cells

Purpose: sulfur mustard (sm) is a potent blistering agent. this alkylating chemical agent has extremely toxic effects on the eye. mmp-2 and mmp-9 are the two most important matrix metalloproteinase enzymes involved in the pathology of chemical eye injuries. curcumin is regarded as a natural anti-inflammatory agent. this study aims to compare the anti-inflammatory effects of curcumin versus doxycycline on chemically induced corneal injuries.methods:the hce-2 cell line was used as a model for corneal cells. the effective concentrations of 2-chloroethyl ethyl sulfide (cees) – as an analog of sm – doxycycline, and curcumin were determined using the mtt assay. the gene expression of mmp-2, mmp-9, and tissue inhibitors of metalloproteinase (timp-1) was evaluated by the real-time pcr method. also, the activity of mmp-2 and mmp-9 enzymes was determined by zymography.results:the expression of the mmp-2 and mmp-9 genes increased 5- and 3.3-fold after exposure to cees, respectively. following the treatment with curcumin and doxycycline, mmp-2 expression decreased significantly. also, after treatment with curcumin and doxycycline, the mmp-9 expression decreased 2.5- and 1.6-fold, respectively. the reduction in activity was 32% for mmp-2 and 56% for mmp-9 after treatment with curcumin. the corresponding values were 12% and 40% following doxycycline treatment. there was no significant difference between the effects of curcumin and doxycycline on reducing mmp-2 expression, but the difference was statistically significant in the case of mmp-9.conclusion:doxycycline and curcumin can inhibit mmp expression and activity in chemically exposed corneal cells. curcumin has a greater ability than doxycycline to inhibit mmp-2 and mmp-9 enzymes; however, the difference is statistically significant only in the case of mmp-9.after further validation, these substances can be introduced as anti- inflammatory agents to treat corneal chemical burns.