Chondrogenic commitment of human umbilical cord blood and umbilical cord-derived mesenchymal stem cells induced by the supernatant of chondrocytes: A comparison study.

BACKGROUND

Native cartilage has low capacity for regeneration because it has very few progenitor cells. Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) and human umbilical cord-derived MSCs (hUC-MSCs) have been employed as promising sources of stem cells for cartilage injury repair. Reproduction of hyaline cartilage from MSCs remains a challenging endeavor. The paracrine factors secreted by chondrocytes possess the capability to induce chondrogenesis from MSCs.

METHODS

The conditioned medium derived from chondrocytes was utilized to induce chondrogenic differentiation of hUCB-MSCs and hUC-MSCs. The expression levels of collagen type I alpha 1 chain (Col1a1), collagen type II alpha 1 chain (Col2a1), and SRY-box transcription factor 9 (SOX9) were assessed through quantitative real-time polymerase chain reaction (qRT-PCR), Western blot (WB), and immunofluorescence (IF) assays. To elucidate the mechanism of differentiation, the concentration of transforming growth factor-β1 (TGF-β1) in the conditioned medium of chondrocytes was quantified using enzyme-linked immunosorbent assay (ELISA). Meanwhile, the viability of cells was assessed using Cell Counting Kit-8 (CCK-8) assays.

RESULTS

The expression levels of Col2a1 and SOX9 were found to be higher in induced hUC-MSCs compared to those in induced hUCB-MSCs. The conditioned medium of chondrocytes contained TGF-β1. The CCK-8 assays revealed that the proliferation rate of hUC-MSCs was significantly higher compared to that of hUCB-MSCs.

CONCLUSIONS

The chondrogenic potential and proliferation capacity of hUC-MSCs surpass those of hUCB-MSCs, thereby establishing hUC-MSCs as a superior source of seed cells for cartilage tissue engineering.