Early TIMP gene expression after corneal infection with Pseudomonas aeruginosa.

PURPOSE To evaluate the expression of tissue inhibitor of metalloproteinases (TIMP) mRNA in corneal tissues before and at early time points (6 and 12 hours and 1, 3, and 5 days) after corneal infection with Pseudomonas aeruginosa. METHODS Ribonuclease protection assays were used to detect and quantitate TIMP mRNA expression in uninfected (wounded and unwounded) and in wounded corneas inoculated with P. aeruginosa. RESULTS Expression of TIMP-1 mRNA was undetectable in either wounded or unwounded, uninfected corneal tissues, but it increased in a time-dependent manner with peak expression occurring at 3 days after corneal wounding and bacterial inoculation. Constitutive low-level mRNA expression of TIMP-2 was detected in both groups of uninfected corneal tissues; these groups remained essentially unchanged after corneal abrasion and bacterial inoculation. TIMP-3 mRNA was detected in uninfected (wounded and unwounded) corneal tissues and appeared to decrease in a time-dependent manner after corneal abrasion and bacterial inoculation. CONCLUSIONS The evidence indicated that TIMPs were expressed in infected and in uninfected (wounded and unwounded) corneal tissues. In addition, these data suggested that TIMP expression appeared to be independently regulated.