Figure 8. Immunolocalization of alpha smooth muscle actin in anterior chamber angles of 1- to 2-month-old mice. Expression of alpha smooth muscle actin (αSMA) is normal in wild-type (WT) mice, demonstrating a well-developed scleral spur (ss) and positive staining within the pupillary muscles (pm). Expression appears decreased in these areas in the matrix metalloproteinase-9 knockout (MMP-9KO) and transgenic (TG) mice. (The trabecular meshwork region is designated by the yellow arrowheads.) This decrease is exacerbated in the TG/MMP-9KO mice. An open chamber angle (red dashed line) can readily be seen in the WT and KO mice but not in TG and MMP-9KO/TG mice. 40X, bar=50 µm.