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. 2006 Jul;169(1):72–85. doi: 10.2353/ajpath.2006.051163

Figure 3.

Figure 3

Characterization of ETCs implanted in the AV groove of adult rat hearts. The expression of gap junction and muscle-specific proteins in cells from implanted ETCs was examined along with vascularization of the implant. A: Low- and high-magnification images of histological (H&E and Masson’s trichrome) staining of sections (5 μm) from an ETC implanted for 2½ years. The right atrium (RA), right ventricle (RV), and ETC are indicated in each micrograph. The suture line is denoted by an asterisk. B: Sections of a Lewis rat heart implanted with a myoblast-containing ETC for 3 years. The panels show regions of implanted tissue stained with desmin, Cx43(α1), α-actinin 2, and L. esculentum lectin, whereas the corresponding insets show an area of the right ventricle. Blood vessels are depicted in green, protein staining is shown in red, and nuclei are depicted in blue. Images represent 10 merged optical sections (0.5 μm) and scale bars (μm) are shown in the bottom left corner of each image. C: Fluorescence in situ hybridization analysis of the AV groove region of the heart of a female rat implanted for 2½ years. Nuclei (blue), Y chromosomes (green), and skeletal type 2 myosin heavy chain, desmin, or Cx43(α1) (red) are shown as are Y chromosome-positive cells (arrows). Arrowheads indicate gap junctions between implanted cells and a cardiomyocyte of the recipient animal. Scale bars represent μm. D: PCR amplification of the rSRY gene in DNA isolated from a male Lewis rat spleen (Sp), a nonimplanted construct (NC) containing mixed gender myoblasts, implanted constructs (IC) containing mixed gender cells dissected from female hearts 1, 6, and 12 months after surgery, and the left ventricle (LV) of a male Lewis rat. LV DNA samples from matching recipient female animals and no DNA (−) served as negative controls. M denotes molecular size standards. E: Immunostaining of sections depicting areas of contact between the recipient heart and the ETC 1 year after implantation. Cardiac-specific (cTnI) or skeletal-specific (type 1 myosin heavy chain) antibody staining (red) is shown in combination with nuclear staining (blue) and staining of a general myogenic marker (α-actinin 2, green). Muscle cells in the ETC are indicated with an asterisk.