Induction of Gelatinase, Collagenases, Stromelysins and Matrilysin by the Corneal Epithelium in Experimental Murine Dry Eye

Abstract

Abstract: : Purpose:To investigate the expression of gelatinase (MMP–9), collagenases (MMP–1 and MMP–13), stromelysins (MMP3 and MMP–10) and matrilysin (MMP–7) by the corneal epithelium in experimental murine dry eye. Methods:White Balb–c mice aged 6–8 weeks were treated with subcutaneous injections of 2.5mg/ml scopolamine hydrobromide, 4 times per day and exposure to an air draft and low humidity for 5 days. Untreated mice were used as controls. Corneal epithelia were lysed in 4M guanidium thiocyanate solution for total RNA extraction and subjected to retrotranscription. Gene expression was evaluated by conventional and real time PCR using mouse specific primers for MMPs and GAPDH, the latter serving as an internal control. Results:The conventional PCR showed the presence of mRNA transcripts for gelatinase (MMP–9), collagenases (MMP–1 and MMP–13), stromelysins (MMP3 and MMP–10) and matrilysin (MMP–7) genes in mouse cornea samples. The use of real time PCR confirmed the conventional PCR results and measured the mRNA levels of all analyzed genes. As normalized with GAPDH house keeping gene, the expression of all MMPs mRNA studied was stimulated in corneal epithelia by 5–day treatment, when compared with untreated control mice Conclusions:These findings demonstrate that gelatinase, collagenases, stromelysins and matrilysin were largely induced in the dry eye mouse model. Further studies are necessary to evaluate their protein production and the mechanism.

Keywords: cornea: tears/tear film/dry eye • cornea: epithelium • inflammation