Decellularized porcine aortic valve scaffolds created by different decellularization protocols: A comparison of their histological, biomechanical, and biocompatible characteristics
- Author:
Li-Xin YANG
1
Author Information
1. Department of Cardiothoracic Surgery
- Publication Type:Journal Article
- Keywords:
Decellularization;
Heart valve prosthesis;
Porcine aortic valve scaffolds;
Tissue engineering
- From:
Academic Journal of Second Military Medical University
2010;28(1):8-12
- CountryChina
- Language:Chinese
-
Abstract:
Objective: To compare the histological, immunological, and biomechanical characteristics of decellularized porcine aortic valve scaffold created by 3 different decellularization protocols and to search for a more suitable technique for creating acellular tissue-engineered cardiac valve conduit. Methods: Porcine aortic valve leaflets and whole aortic roots were decellularized by 3 different protocols. Decellularization procedure in group I involved treatment wit 0.01% trypsin, 1% Triton, and nuclease for 24 h; that in group II involved treatment with 0.01% trypsin (8 h), 1% DCA, and nuclease for 24 h; and that in group III involved treatment with 1% DCA and nuclease for 32 h. All the treatments were conducted during continuous shaking at 37°C. Porcine aortic valve leaflets and whole aortic roots treated with PBS were taken as control. The decellularization efficiencies of each protocol were assessed by H-E staining, scanning electron microscopy, and transmission electron microscopy. The biomechanical features of the acellular valve matrices were examined by stress-strain tests and tensile strength tests. The immunogenicity and inflammatory responses of the decellularized matrices, valve leaflets, and aortic wall were investigated by subcutaneous implantation of them in rats. Results: The native cells in porcine aortic valve leaflets and aortic roots were completely removed in group II, which was superior to group I and III. The values of elasticity modulus and ultimate tensile strength (UTS) of group II were greater than those in group I ([5.77±0.95] MPa vs [4.15±1.13] MPa and [7.82±1.51] MPa vs [4.65±0.85] MPa, respectively; P<0.05). The extension ratios ar 1.5 MPa and at rupture in group II were less than those in group I ([0.33±0.04] vs [0.41±0.09] and [0.45±0.02] vs [0.60±0.06]; P<0.05), but the extension ratio at rupture was similar to that of fresh porcine aortic valves ( [0.45±0.02] vs ([0.46±0.03]). Histological analysis showed only slight inflammatory responses in groupIIand the host cells grew into the matrix, rebuilding the acellular matrices gradually. Conclusion: Decellularization using 8-hour pretreatment with 0. 01% trypsin, followed by 24 hours incubation with 1% DCA plus nuclease is effective and convenient; it not only removes the cells but also decreases the immunogenicity of the aortic valve matrices, making the product an excellent material for tissue-engineered cardiac valve conduit.
