Fig 1: Collagen synthesis is affected in MMP-9 null mice. (a) qPCR analysis of Col1a1 mRNA expression reveals a (nonsignificant) reduction of approximately 50% in collagen I synthesis in MMP-9 null mice in comparison to wild-type mice (n = 6, Student's t-test). (b) Overview picture of a collagen I immunostaining of the anterior chamber angle region, showing reduced collagen I expression in the trabecular meshwork and the sclera of MMP-9 null mice. Scale bar: 50 µm. (c) High-magnification image of collagen I staining in the trabecular meshwork, revealing nearly complete absence of collagen I staining in the trabecular beams of MMP-9 null mice (*). Scale bar: 10 µm. (d) qPCR analysis of Col4a3 mRNA expression reveals a (nonsignificant) reduction of approximately 50% in collagen IV synthesis in MMP-9 null mice in comparison to wild-type mice (n = 6, Student's t-test). (e) Overview picture of collagen IV immunostaining of the anterior chamber angle region reveals that immunostaining intensity is slightly reduced in the trabecular meshwork of MMP-9 null mice. Scale bar: 50 µm. (f) High-magnification image of collagen IV staining in the trabecular meshwork confirms reduced collagen IV immunolabeling. Scale bar: 10 µm.