TIMP-1 DNA inhibits MMP-9 activity at day 2 after infection. Groups of animals were treated twice with 100 μg of TIMP-1, vector, and β-gal DNA intraocularly 6 and 3 days before virus infection and were infected with 106 PFU of HSV-1 RE on their scarified corneas 3 days after a second treatment of DNAs. At day 2 after infection, animals were sacrificed, and corneas were excised and pooled from six eyes and homogenized. Corneal extract samples (20 μg/lane) were analyzed by gelatin zymography. Lane 1: human zymography standard; lane 2: corneas treated with vector DNA; lane 3: corneas treated with β-gal DNA; lane 4: corneas treated with TIMP-1 DNA. The data represent a single experiment from two independent experiments with four mice in each group.