FIG. 4.

Serial sections of the LVI (area within dotted lines) at day 1 post-MI show that CS staining dramatically declines when MMP-9 is present. The left panels show representative pictures of WT animals, with high MMP-9 and low CS expression levels in the LVI. The right panels show serial sections of MMP-9 null mice with CS expression in the LVI area, suggestive of in vivo MMP-9 cleavage of CS. Top panels: Immunostaining for CS (positive staining is dark purple). Bottom panels: Immunostaining for MMP-9 (positive staining is dark brown; arrows show positive staining), 40×magnification.