Various decellularization methods for allogenic and xenogenic bioscaffolds have been previously reported; however, decellularization methods for very thin (submillimeter-diameter) vascular tissues have not been discussed well. In this study, rat tail arteries (inner diameter, 0.6 mm) were decellularized with peracetic acid (PAA) and DNase I. PAA treatment is expected not only to disrupt cell membranes which improves the decellularization efficiency in the subsequent DNase treatment, but also to sterilize vascular scaffolds. We succeeded in adequate cell removal by immersing in 0.3% isotonic PAA solution and subsequent washing with DNase solution. For the DNase washing process, the perfusion method was superior in terms of cell removal to the static immersion method. Graft lumen was modified with a peptide composed of a collagen binding sequence and endothelial progenitor cell-binding sequence, (Pro-Hyp-Gly)7-Gly-Gly-Gly-Arg-Glu-Asp-Val, as previously reported. They were patent in rat allogeneic transplantation model for 2 weeks, but unexpectedly resulted in graft rupture or tear formation, thereafter, suggesting reduced mechanical strength of the decellularized scaffolds. Histology showed that the thickness of the extracellular matrix (ECM) was decreased by the perfusion of the DNase solution. The method of combination of PAA and DNase was not necessarily optimal for the decellularization of very thin vascular tissues. The decellularization method is a compromise between effective cell removal and maintenance of the ECM nature. Since the acceptability of ECM denaturation by the host tissue highly depends on individual cases, decellularization methods should be carefully selected according to the type of target tissue and its intended use.
Keywords: Decellularization; Peracetic acid; Tissue engineering; Vascular graft.