Fig. 5

Tetracycline reduces pulmonary fibrotic remodeling in silica exposed mice. C57BL/6 J mice were challenged with silica (SIL) (0.33 mg/mouse) i.t. on days 0, 7, 14 and 21 and treated by i.p. injection of tetracycline (TET) every 24 h for 10d and afterwards 3 times a week. Mice (PBS+PBS (n = 5) SIL+PBS (n = 9) SIL+TET (n = 9)) were sacrificed 12 weeks after instillation. Representative H&E and sirius red stained histologic sections are shown (magnification, 400×) (A). Lung injury score was determined by examining 15 sections/lung/animal (n ≥ 5 per group, magnification × 100) (B). Pulmonary collagen levels were quantified by SIRCOL collagen assay (C). Median with interquartile range of 3 independent experiments, Mann–Whitney Test