Fig. 1
MMP-9 knockout enhances systemic inflammatory response after LPS administration. (A) Schematic overview of the in vivo experimental workflow. WT and MMP-9 KO mice received intraperitoneal LPS injections (4.5 mg/kg) for either 4–24 h. (B, C) Plasma concentrations of IL-6 and TNF-α were measured at the indicated time points. (D) Representative hematoxylin and eosin (H&E)-stained liver sections from each group. Central vein (CV) and immune cell infiltration (black arrow) are indicated. Scale bar = 100 μm. (E) Immunohistochemical staining of F4/80 in liver tissue. CV denotes the central vein. Quantification of F4/80-positive area is shown. Scale bar = 100 μm. (F) Representative zymography and immunoblotting of MMP-9 enzyme activity and protein expression in total liver lysates. (G) Densitometric analysis of mutated MMP-9 expression normalized to GAPDH. All LPS treatments were performed for 24 h unless otherwise specified. Data are presented as mean ± SEM (n = 4–8 per group). Statistical comparisons were performed using unpaired t-tests. *P < 0.05, **P < 0.01, ***P < 0.001 vs. WT + LPS; ns: not significant.
