FIG. 6.

The increase in MMP-9 in the BMZ induced by NM is attenuated by tetracycline derivatives. Three sections illustrating MMP-9 distribution patterns in each treatment group from a typical NM exposure experiment. Top row: unexposed controls had low levels of MMP-9 and background staining in the epithelium; row 2: NM greatly increased MMP-9; rows 3–6: corneas exposed to NM, followed by treatment with a tetracycline derivative for 24 h. Green: MMP-9 antibody staining; blue: DAPI-stained nuclei. MMP, matrix metalloproteinase; san, sancycline.