Previously, we established a novel and simple bone marrow high-density culture system by seeding BMNCs in HD dots on tissue culture plates. Pre-coating of the plates and addition of growth factors are not required using this culture technique. Cells expanded in HD culture display EPC characteristics and have high proangiogenic potential. In addition, the cells secrete higher levels of vascular endothelial growth factor and hepatocyte growth factor, compared with cells grown in regular-density culture. On the basis of these advantages, we speculate that these cells might be better than cells from RD culture, for the treatment of liver fibrosis. To test this hypothesis, the antifibrogenic and regenerative effects of highand RD cultured bone marrow cells were investigated in a carbon tetrachloride -induced rat chronic liver fibrosis model. Liver tissues were fixed in 4% paraformaldehyde for 12 h, Vecuronium Bromide embedded in paraffin and cut into 5-mm sections. E-7046 sections were stained with hematoxylin and eosin, picric acid-sirius red, and Masson, for histological structure analysis and fibrosis area analysis. Five randomly selected fields of view, from PSR- and Masson-stained sections of each sample, were captured by a light microscope.The fibrosis area was measured using Image-Pro Plus software. The percentage fibrosis area was calculated by comparing the collagen stained area to the total area of the fields examined. To detect cell distribution in the liver after intrasplenic injection, liver tissues were harvested at 4 weeks post-transplantation, embedded in OTC compound and frozen slides were sectioned at 10 mm. Three mice from each group and three sections from each mouse, were stained with FITC-conjugated anti-collagen type I and DAPI, and were observed under a confocal microscope. The number of CM-DiL-labeled cells was calculated from five fields of view for each sample by Image-Pro Plus software. As shown in Fig. 2, both ALT and AST were significantly increased in the PBS-treated group, but not in the group that received HD cultured cells.