Increased BM and spleen fibrosis in Tsp-1–null TPO^high mice. (A) Representative histologic sections of femurs (top panels) and spleen (bottom panels) from WT TPO^high mice or Tsp-1–null TPO^high mice at week 12 after engraftment. Silver staining reveals BM and spleen fibrosis in both TPO^high groups of mice. Images were obtained using a Leica DMRB microscope (total original magnification ×250) 25×/0.85 NA objective and acquired with a Video 3 charge-coupled device Sony Leica Power hole accumulated diode camera. (B) An increased fibrosis was observed in both BM and spleen from Tsp-1–null TPO^high mice (□) compared with WT TPO^high mice () at weeks 8 or 12 after engraftment. Total area of reticulin fibers was quantified using ImageJ software. Results of statistical analysis with the Wilcoxon test are as follows: WT TPO^high mice versus Tsp-1–null TPO^high mice: **P < .001.