The Effects of bFGF, VEGF and Micromass Culture on Proliferation and Differentiation of Human Chondrocytes

Chung, Ho Yun; Moon, Jeong Hwan; Yang, Jung Dug; Lee, Dong Gul; Cho, Byung Chae

Abstract

The acquisition of human chondrocytes for transplantation and cartilage coverage presents a major problem as these cells dedifferentiate rapidly during expansion in monolayer culture. Dedifferentiated chondrocytes change their shapes, metabolic states, and programs of matrix biosynthesis. We initiated this study on the basis of the hypothesis that bFGF, VEGF, and micromass culture can influence both the proliferation and their ability to express COL2A1 gene as a chondrogenic marker and Cbfa1 gene as an osteogenic marker. Chondrocytes in monolayer and micromass culture with or without bFGF and VEGF in vitro were collected and analyzed. In results, bFGF stimulated the proliferation of chondrocytes in monolayer culture. VEGF also stimulated the proliferation, but was less effective. The phenotype of chondrocytes was gradually changed in monolayer culture. Chondrocytes expanded in the presence of bFGF became dedifferentiated. However, dedifferentiated chondrocytes fully maintained their potential for redifferentiation in response to environmental changes. After transferring in micromass culture, chondrocytes which expanded with bFGF demonstrated high COL2A1 expression that was biochemically comparable to primary chondrocytes. Chondrocytes which expanded with VEGF demonstrated high Cbfa1 expression in both monolayer and micromass culture with passage times. This study provides that bFGF is needed to expand chondrocytes during tissue cultivation and additional three-dimensional environment is needed to maintain their differentiated phenotype. VEGF initiates the osteogenic potential during the chondrocyte expansion especially in micromass culture.