Identification of CD68 positive cells in liver. (A) CCl4-treated mice. CCl4 induced Kupffer cells (representative cells indicated by head arrows) activation at day 5. At day 8 were also evident activated mega macrophages (arrows) that were organized to form cellular clusters localized exclusively in necrotic areas. (B) High magnification of CD68 positive cellular clusters (red square in A). Mega macrophages were endowed with phagocytic activity as demonstrated by PAS-D stain (right image). (C) UCMSCs transplantation in CCl4-treated mice. The amount of CD68 positive cells was reduced at day 5 compare to CCl4-trated mice. After 8 days there were few CD68 positive cells, as detected in control mice liver. (D) Control (PBS) mice liver. Scale bars: 200 μm.