No correlation of chondrogenic differentiation with donor age and gender.

<p>5×10<sup>5</sup> MSC were subjected to six weeks of chondrogenic induction in high density culture. From 6 parallel pellets per donor, 2 pellets were used for histological stainings, 2 pellets were processed for quantification of glycosaminoglycan deposition and 2 pellets for quantification of collagen type II deposition. (A) Immunohistochemical staining for collagen type II was used to confirm chondrogenic differentiation and the chondrocyte-like morphology of the cells. Staining varied from full to negative depending on the donor with similar variability in all age groups (A, inset). (B) The collagen type II content determined after pepsin digestion of pellets by ELISA revealed a weak trend of reduced chondrogenesis at older age. (C) Glycosaminoglycan deposition determined after staining the pellets with Alcian blue dye, washing and extracting the dye revealed a trend of reduced chondrogenesis at older age. (D) Collagen type II deposition in pellets from female and male donors showed no significant differences. Correlation was calculated by Spearman-Rho Test, group comparison by Mann-Whitney-U Test.</p>