BACKGROUND:?Stem?cell?transplantation?provides?a?theoretical?approach?for?liver?regeneration?medicine;?it?may?promote?liver?regeneration? and? self-repair.? However,? the? transplantation? of?bone? marrow-mesenchymal? stem? cells? expanded? ex vivo? as? a?therapy?for?liver?disease?has?rarely?been?investigated.?This?study?aimed? to? explore? whether? bone? marrow? stem? cells? expanded?ex vivo?home?to?the?liver?and?foster?hepatic?recovery?after?CCl4?injury. METHODS:?Bone? marrow? cells? from? BALB/c? mice? were?expanded?ex vivo?by?multiple-passage?cultivation,?characterized?by?cytoflow?immunofluorescence,?and?pre-labeled?with?PKH26?before?intravenous?infusion?into?animals?treated?with?CCl4.?The?integration?of?bone?marrow?cells?into?the?liver?was?examined?microscopically,?and?plasma?hepatic?enzymes?were?determined?biochemically. RESULTS:?Cultured? bone? marrow? cells? exhibited? antigenic?profiles?comparable?to?those?of?primary?medullary?stem?cells.?Double? immunofluorescence? showed? colocalization? of? these?cells?with?proliferative?activity?and?albumin?expression?in?the?liver?of?CCl4-treated?mice.?Densitometry?showed?increased?in situ? cell? proliferation? (50±14? vs? 20±3? cells/high-power? field,?P