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Tissue engineering is considered a promising future option for nasal cartilage repair. However, until now, an optimal material has not been identified for this specific purpose. Therefore, the aim of this study was to analyze a recently developed decellularized collagen matrix, which has promising material properties for septal cartilage repair. A tetrazolium dye based cytotoxicity assay using rat nasal septum chondrocytes was performed to examine the cytotoxic effects of decellularized cartilage matrices. Unseeded scaffolds as well as scaffolds seeded with chondrocytes were implanted in nasal septum defects in Lewis rats to investigate the cellular and humoral inflammatory responses in the surrounding tissue as well as the effect on the formation of nasal septum perforations. Samples were analyzed histochemically and immunohistochemically after 1, 4, and 12 weeks. Although cells for the cytotoxicity assay were cultured under serum-free conditions for 24 h to increase sensitivity, no cytotoxic effects were detected. Histological and immunohistochemical evidence displayed that the implanted scaffolds induced minor macrophage and lymphocyte infiltration and were well integrated at the contact site to native cartilage and between the mucosal membranes. The biocompatibility index revealed only slightly irritating effects during the study period. Septal perforations were prevented efficiently. In summary, our results provide evidence that decellularized xenogeneic collagen scaffolds are suitable for cartilage tissue engineering. The scaffolds were integrated well into septal cartilage defects without causing a strong inflammatory reaction and prevented the development of nasal septum perforations. Therefore, we envision the possibility to use them in nasal cartilage repair in the future.

Objectives: Decellularization of porcine septum cartilage is necessary for its application as xenogenic replacement material. The aim of this study was to investigate spatial differences of structure and composition in the whole native and decellularized porcine nasal septum. Subsequently, the results shall be compared with studies of human nasal septum. Methods: Ten porcine nasal septa were divided into six regions from caudal to cephalic and four regions from dorsal to ventral to create a grid of 24 approximately equal segments. All segments of five septal cartilages were decellularized separately by a wet chemical multistep procedure. The segments were analyzed to determine quantitative amounts of total collagen, chondrocytes, and sulfated glycosaminoglycans (sGAG). Results: The distribution of cell number showed no significant differences between the individual regions. For the distribution of collagen and sGAG, no significant differences could be identified from caudal to cephalic, both in native and decellularized tissue. From dorsal to ventral, native and decellularized nasal septum showed significant differences between individual regions. In native septum, linear regression analysis indicated a decreasing collagen and an increasing sGAG content from dorsal to ventral. After decellularization, an increasing collagen and a decreasing sGAG content was detected. Conclusion: The results of this study showed slightly but significant differences in the distribution of collagen and sGAG from dorsal to ventral. From caudal to cephalic, no differences could be observed. Compared to human, nasal septum differences in cell, collagen, and sGAG content were detected. Despite this, human and porcine nasal septum showed similar distributions and a consistently inverse linearity of collagen and sGAG content. Nevertheless, the midcaudal and midcephalic regions showed the highest porosity and a high stability and thus offer the best conditions for the revitalization of porcine tissue by human cells. [ABSTRACT FROM AUTHOR]

The implantation of autologous cartilage as the gold standard operative procedure for the reconstruction of cartilage defects in the head and neck region unfortunately implicates a variety of negative effects at the donor site. Tissue-engineered cartilage appears to be a promising alternative. However, due to the complex requirements, the optimal material is yet to be determined. As demonstrated previously, decellularized porcine cartilage (DECM) might be a good option to engineer vital cartilage. As the dense structure of DECM limits cellular infiltration, we investigated surface modifications of the scaffolds by carbon dioxide (CO2) and Er:YAG laser application to facilitate the migration of chondrocytes inside the scaffold. After laser treatment, the scaffolds were seeded with human nasal septal chondrocytes and analyzed with respect to cell migration and formation of new extracellular matrix proteins. Histology, immunohistochemistry, SEM, and TEM examination revealed an increase of the scaffolds' surface area with proliferation of cell numbers on the scaffolds for both laser types. The lack of cytotoxic effects was demonstrated by standard cytotoxicity testing. However, a thermal denaturation area seemed to hinder the migration of the chondrocytes inside the scaffolds, even more so after CO2 laser treatment. Therefore, the Er:YAG laser seemed to be better suitable. Further modifications of the laser adjustments or the use of alternative laser systems might be advantageous for surface enlargement and to facilitate migration of chondrocytes into the scaffold in one step. [ABSTRACT FROM AUTHOR]