Adipose Tissue as a Useful Material for the Grafting of Tumorigenic Cells and Juvenile Tissues in Mice

Although the aging process expands the adipose tissue habitation in mice and due to its close association with the female reproductive system, it can be easily exposed surgically under anesthesia when reproductive organs (including ovary, oviduct, and part of the uterus) are pulled and exposed onto the dorsal skin. This study aimed to consider the suitability of adipose tissue as a target for manipulation, particularly for the grafting of cells or small-sized tissue sections due to its ease of handling. Subsequently, 1-2 µL trypan blue injections were administered to the tissues using a breath-controlled micropipette under a dissecting microscope for evaluating the adipose tissue’s potential as a suitable grafting material. It was observed that the injected dye remained at the injection site for at least one day after injecting B16 mouse melanoma and P19 embryonal carcinoma cells. It resulted in the generation of solid tumors surrounding the ovary, oviduct, or uterus with 100% efficiency, as reported by an inspection one and a half months after the injections. When the grafting procedure was carried out for one-fourth of the juvenile pancreas (aged 15 days), an enlarged pancreas with normal morphological configuration (including the formation of insulin-synthesizing cells) was generated, which was observed by an inspection one month after the injections, thus successfully validating our approach for adipose tissue manipulation and furthermore, naming this novel technology as “intra-adipose introduction of cells and tissues”.

Studies on Connexin 43, a Gap-Junction Protein, in P19 Embryonal Carcinoma Cells after Culture on an Apatite Fiber Scaffold

We previously showed enhanced osteoblast differentiation by culturing cells in apatite-fiber scaffold (AFS). The well-developed a-surface of the apatite fibers provides favorable structural features and chemical interactions with the cells, and the scaffold appears to affect cell differentiation. AFS was used here to study its utility for soft-tissue engineering. An embryonal carcinoma cell line, P19.CL6, was cultured in AFS, and the expression and phosphorylation of a gap-junction protein, connexin 43 (Cx43), during cell proliferation and differentiation was examined. We show that treatment with dimethyl sulfoxide appears to induce a change in the isoform composition of Cx43 under the control condition, but not in AFS. We also show that serum starvation induces the phosphorylation of Ser 368 of Cx43 only in functionally mature cells.