Cardiac IL-6 is elevated but does not mediate uPA-induced cardiac fibrosis.

A. IL-6 concentrations in explant culture media from hearts of SR-uPA+/0 and NTG mice. N  = 5 mice per genotype. B. Collagen content of hearts from SR-uPA+/0 and NTG littermates at 15 weeks of age. Solid circles represent mice heterozygous for IL-6; open circles are mice homozygous (+/+ or −/−) for IL-6. Bars are medians. N  = 3–5 mice per heterozygous or homozygous genotype. C. Macrophage accumulation in hearts of SR-uPA+/0 and NTG littermates at 7 weeks of age. Solid circles represent mice heterozygous for IL-6; open circles are mice homozygous (+/+ or −/−) for IL-6. Bars are medians. N  = 3–5 mice per heterozygous or homozygous genotype. Representative heart sections stained with picrosirius red of D. NTG mice, E. SR-uPA+/0 il6+/+ and F. SR-uPA+/0 il6−/− mice. Bars represent 100 µm.