FIG. 5.

Subcutaneous implants of lungs decellularized with pH 8, pH 10, and pH 12. CHAPS reveal differences in host immune reactivity, and concomitant infiltrating cells, when implanted into immunocompetent rats. Gross images of native (A) and acellular lung tissues (B–D) that were decellularized at pH 8 (B), 10 (C), or 12 (D) and subsequently subcutaneously implanted into immunocompetent rats for 7 days. Explanted lungs were visually inspected for evidence of immune reaction from the donor. A strong immune reaction was observed with the native implant as evidenced by blackened tissue, and the decellularized tissue demonstrated a loss in color (primarily red) with increasing pH. H&E images of native (E, l), and acellular lung tissues decellularized at pH 8 (F, J), 10 (G, K), or 12 (H, L). The pH 8 lungs largely maintained tissue architecture maintenance, and of the tissues demonstrated the lowest evidence of fibrotic tissue formation. In addition, it appears that the majority of infiltrating cells are red blood cells found in the vasculature (J). After 7 days, both pH 10 and 12 tissue samples were comprised of very dense tissue, with little evidence of alveolar structure retention. Decellularized lung implants had an average weight of 197 mg (SD±72 mg). Scale bars=50 μm. Color images available online at www.liebertpub.com/tec