Wild-type and MMP-7–/– knockout mice were treated with continuous infusions of Ang II (1.5 mg/kg/d). (A) Albuminuria is significantly reduced in the knockout compared with wild-type mice. (B) Gel electrophoresis of urine samples demonstrates a reduced albumin excretion in MMP-7–/– mice, compared with MMP-7+/+ counterparts. (C) Immunofluorescence staining shows extensive nephrin disruption and a decrease in numbers of healthy WT1-positive podocytes in MMP-7+/+ mice. MMP-7–knockout mice retained linear nephrin staining and numbers of WT1-positive nuclei (original magnification, ×40). (D) Quantitation of WT1-positive nuclei per glomerulus (n = 5–6, t test). (E and F) Western blot analyses show an increased preservation of WT1 expression in MMP-7–/– mice after Ang II infusion, compared with MMP-7+/+ controls. Western blot (E) and quantitation (F) are shown. *P < 0.05 (n = 4–5, t test).