Beyond DNA removal: assessing the immunological response to decellularized rabbit dermal matrices

Introduction: Decellularized matrices have attracted considerable attention in tissue engineering and regenerative medicine due to their ability to preserve the biochemical composition and microarchitecture of native tissues. Although DNA removal is commonly used as the main indicator of decellularization efficiency, other factors—such as endotoxin contamination, damage-associated molecular patterns, and residual reagents—can significantly influence the host immune response. In this study, decellularized rabbit dermal matrices (dRDM) produced using two different protocols— resulting in DNA levels below or above the proposed safety threshold of 50 ng/mg dry tissue—were evaluated for their immunological performance. Conclusions: Two decellularization protocols produced dRDMs with distinct biological profiles. Although the SDC 3H protocol achieved DNA levels below the recommended threshold, it was associated with greater collagen degradation, whereas the SDC 30 min protocol better preserved native dermal collagen. Both matrices were sterile, endotoxin-free, and did not induce ROS production in PBMCs. However, dry dRDMs and SDC 3H-treated matrices promoted complement activation and increased PBMC necrosis. Overall, despite not meeting the recommended DNA threshold, the SDC 30 min protocol demonstrated superior immunocompatibility and collagen preservation, highlighting that DNA content alone is not a reliable predictor of decellularization efficiency. Instead, immunocompatibility, collagen integrity, physical cell–matrix interactions, and potential detergent residues play a critical role in defining matrix performance.