Fig. 5. In vivo contribution of eGFP-MSCs into bronchiolar epithelial, hepatocyte and renal tubular-like cells. (A) Representative paraffin sections of lung stained either with rabbit immunoglobulins (isotype control) (A1) or with rabbit anti-pan-CK antibodies (A2). Serial sections (A3,4) show that a group of pan-CK+ cells (red) (A4) also stained positive for eGFP (A3). (B) Representative liver sections with hepatocytes staining positive for eGFP (B1,2; brown). eGFP expression coincided with albumin (red) giving a brown-purple staining (B2, inset). Serial paraffin sections from another liver showing purple cells with hepatocyte morphology, as a result of co-expression of eGFP (red) and CK18 (blue) (B4). Isotype control sections shown in B3. (C) Differentiation of eGFP-MSCs into renal tubular cells. Paraffin-embedded sections stained with isotype control antibodies show no background staining (C1). Arrows indicate eGFP⁺ cells after staining with rabbit anti-eGFP antibody (C2,3) co-expressing both lectins Ricinus communis (C2, bottom-center inset; red staining) and Lotus tetragonolobus (C4; pink-red staining) as shown in serial sections. A frozen section of a kidney demonstrating eGFP⁺ cells by direct visualization using a fluorescent microscope (C5). All sections were counterstained with hematoxylin (except for B4) or DAPI (C5). Magnifications: x100 (A1,2); x200 (C1,2,5); x400 (A3,4, B1-4, C3,4).