Little evidence of bone marrow-derived hepatocytes in the replacement of injured liver

Abstract

We have tested the ability of bone marrow (BM) cells (BMCs) to form hepatocytes in liver injury models. We used three models: (i) carbon tetrachloride (CCl4) treatment, (ii) albumin-urokinase transgenic mouse [TgN(Alb1Plau)], and (iii) hepatitis B transgenic mouse [TgN(Alb1HBV)]. As a nonselective liver injury model, irradiated C57BL/6 (B6) mice were transplanted with BMCs from GFP transgenic mouse [TgN(ActbEGFP)] or beta-galactosidase transgenic mouse [TgN(MtnLacZ)] followed by the administration of CCl4. Irradiated TgN(Alb1HBV) and TgN(Alb1Plau) were also transplanted with BMCs from TgN(ActbEGFP) or TgN(MtnLacZ). Approximately 1.5 x 106 hepatocytes per liver were analyzed for GFP-positive cells, and the whole livers were inspected for beta-galactosidase expression. No GFP-positive hepatocytes and no gross blue staining of the livers with 5-bromo-4-chloro-3-indolyl beta-d-galactoside in any of the 18 recipient mice analyzed were detected. The livers from female animals with gender-mismatched BM transplantation were also tested with Y chromosome fluorescent in situ hybridization analysis to detect donor-derived cells. A total of five isolated hepatocytes were positive for Y chromosome in 4.1 x 105 hepatocytes analyzed. Our results demonstrate that there is little or no contribution of BMCs to the replacement of injured livers in these models. We conclude that BM-derived cells cannot generally lead to a cure of liver damage.

Fig. 1.

(A) GFP-positive nonhepatocytes observed in a liver section from CCl₄-treated mouse. Bromo-4-chloro-3-indolyl β-d-galactoside (X-gal) staining of the whole liver from TgN(MtnLacZ) as a positive control (B) and B6 transplanted with TgN(MtnLacZ) BM mononuclear cells and administered CCl₄ (C). No X-gal positive nodule was observed in the B6 liver. (D) Y chromosome-positive hepatocyte nucleus (arrow) from a mouse in CCl₄ liver injury model. (Scale bars: 50 μm, A; 30 μm, D.)