Figure 4.

Devitalization and lyophilization of MSOD‐B cartilage result in an off‐the‐shelf graft material with preserved composition and bone formation capacity. a) Cartilage tissues were engineered by chondrogenic culture of MSOD‐B (MB) (Living group), subsequently devitalized by apoptosis induction (Devitalized) and further lyophilized (Lyophilized) through a freeze‐dry process. The impact of the devitalization and lyophilization processes was analyzed by mass‐spectrometry and functional in vivo implantation. b) Venn diagram displaying the shared or unique identified proteins within the respective groups. A total of 2456 protein—present in at least 3 biological replicates from the respective groups—were identified. The large majority of detected proteins was common to the three groups (77%, 1892 proteins) (n = 5). c) The devitalization and lyophilization of MB cartilages minimally affected their composition, as assessed through mean abundance analysis of extracellular proteins detected in each biological groups. Proteins displaying a significantly different abundance (between at least 2 groups) are highlighted in red (q‐value ≤ 0.05) (n = 5). d) Similarity score between Living, Devitalized, Lyophilized tissues, and human primary tissues (tibial condyle and meniscus). The score is derived from the abundance ranking of 34 cartilaginous proteins (see ref. ^{[ 21 ]}) and highlights the compositional similarity of MB engineered tissues. e,f) The devitalization and lyophilization did not affect the bone formation capacity of MB cartilage tissues, as assessed by histological (Saf‐O, Collagen type II) and µCT analysis of in vitro and subcutaneously implanted grafts. Scale bars = 100 µm. Bern score (n ≥ 4) quantification of in vitro tissues. Bone volume (BV) as a percentage of total volume (TV) (n = 6) and ossicle maturity scoring (n = 6) analyzed from in vivo implanted tissues. The graphs represent mean + SD. Statistical analysis based on two‐tailed unpaired t‐tests.