Osteochondroprogenitor cells: isolation, identification and chondrogenesis under the induction of transforming growth factor beta3 / 中国组织工程研究

ABSTRACT

BACKGROUND: Precartilaginous stem cells exist in articular cartilage, which may become potential seed cells for cartilage tissue engineering. Transforming growth factor-β3 (TGF-β3) has positive regulation effect on the proliferation and chondrogenic differentiation of precartilagious stem cells. OBJECTIVE: To investigate the effect of TGF-β3 on the chondrogenesis of osteochondroprogenitor cells. METHODS: CD146+chondrocytes were isolated from the patients with advanced osteoarthritis, and were then identified. CD146+chondrocytes were cultured in the normal medium (blank control group), chondrogenic induced medium (control group), chondrogenic induced medium containing 2.5 and 10 μg/L recombinant human TGF-β3, respectively. The immunohistochemistry of collagen Ⅱ and aggrecan was performed, and the related gene expression was tested by real-time quantitative PCR after 4 weeks of culture. RESULTS AND CONCLUSION: When chondrogenic differentiation was performed, the number of cell pellets in the 10 μg/L TGF-β3 group was greater than that in the 2.5 μg/L TGF-β3 group, and the number of cell pellets in the 2.5 μg/L TGF-β3 group was greater than that in the control group. The expression levels of collagen Ⅱ and aggrecan in the 10 μg/L TGF-β3 group was significantly higher than that in the 2.5 μg/L TGF-β3 group (P＜ 0.05). The expression levels of collagen Ⅱ and aggrecan in the 2.5 μg/L TGF-β3 group were significantly higher than those in the control group (P＜ 0.05). Real-time quantitative PCR results showed that the expression levels of collagen Ⅱ and aggrecan mRNA in the 10 μg/L TGF-β3 group were significantly higher than those in the 2.5 μg/L TGF-β3 group (P＜ 0.05), but the expression level of SOX-9 showed insignificant difference between two groups (P ＞ 0.05), and the expression level of SOX-9 in the 10 and 2.5 μg/L TGF-β3 groups was significantly higher than that in the control group (P＜ 0.05); the expression levels of collagen Ⅱ and aggrecan mRNA in the 2.5 μg/L TGF-β3 group were higher than those in the control group (P＜ 0.05). Our findings suggest that osteochondroprogenitor cells with stem cell characteristics exist in the residual articular cartilage of the patients with advanced osteoarthritis. TGF-β3 has the ability of promoting chondrogenic differentiation of osteochondroprogenitor cells, which may be an ideal cytokine for cartilage tissue engineering.