Abstract
Mesenchymal stem cells (MSCs) from various sources have been used in cartilage differentiation with variable success. Therefore, it is
of interest to evaluate the in vitro differentiation potential of the hWJSCs derived from the human umbilical cords into chondrocytes at
the stem cell research facility at the King Abdulaziz University. hWJSCs are an attractive choice for tissue engineering and regenerative
medical applications including cartilage regeneration. We evaluated the hWJSCs using classical histological and cartilage related gene
expression studies. Some of the known parameters were re-examined for consistency at the current laboratory conditions. Early
passages (P1-P4) showed short fibroblastic morphology and high expression of MSC related surface markers namely CD29 (99.9%),
CD44 (97.8%), CD73 (99.6%), CD90 (95.1%) and CD105 (98.9%). MTT assay showed time dependent increase in hWJSCs proliferation by
61.06% and 206.31% at 48h and 72h respectively. Toluidine blue histology showed that hWJSCs were successfully differentiated into
chondrocytes in chondrocytic differentiation medium for 21 days. Differentiated hWJSCs also showed significantly increased
expression of collagen type II, aggrecan and SOX9 compared to the undifferentiated control. It should be noted that the determination
of the average cell yield, the population doubling time and histological staining wtih alcian blue and/or safronin O is required in future
studies for improved evaluation of differentiation. Painless derivation, abundance of stem cells that are hypo-immunogenic and safety
issues makes this method advantages to MSCs derived from other sources.