Objective      To determine the effects of Wnt3a/β-catenin signaling on the aging of human mesenchymal progenitor cells (MPCs).       Methods      The expression of Wnt3a and β-catenin in MPCs from normal human cartilage tissues and osteoarthritis (OA) cartilage was detect

ed by RT-PCR and Western blotting. Then

Western blotting was used to detect the accumulation of β-catenin protein in normal human MPCs after the Wnt3a/β-catenin signaling activation or blocking. MTT assay was applied to measure cell proliferation. The expression of Collagen II

aggrecan and SOX9 at mRNA level was studied in MPCs from normal and OA cartilage tissues under inducing into cartilage-like cells.       Results      The expression of Wnt3a and β-catenin proteins was significantly higher in OA MPCs than that in normal human MPCs. The accumulation of β-catenin proteins was increased in the normal human MPCs after the Wnt3a/β-catenin signaling pathways activation

and reduced after blocking the Wnt3a/β-catenin signaling pathways. Cell proliferation was lower in the normal human MPCs after the Wnt3a/β-catenin signaling pathways activated than in the normal human MPCs

and restored after blocking the Wnt3a/β-catenin signaling pathways. Wnt3a/β-catenin signaling pathways activation resulted in decreased mRNA expression of Collagen II

aggrecan and SOX9 in normal human MPCs after induced to cartilage-like cells （

P

<

0.01）. While

the expression of above genes was restored after blocking the Wnt3a/β-catenin signaling pathways (

P

<

0.05). There was no difference between the normal human MPCs and the normal human MPCs after blocking the Wnt3a/β-catenin signaling pathways.       Conclusion      Wnt3a/β-catenin signaling pathways activation promotes the aging of MPCs

and

blocking the pathways it inhibits the aging. The Wnt3a/β-catenin signaling pathways may play an important role in OA.