COL2A1 and fetal growth restriction: In the present study, after chondrogenic differentiation, the glycosaminoglycan content, as measured by Safranin-O and Alcian blue staining, and the expression levels of phenotypic genes, including COL2A1 and ACAN, as well as the expression of TGFβRI, were decreased in the IUGR group, suggesting that the low expression of TGFβRI led to the reduced responsiveness to TGFβ1 and further resulted in the poor differentiation of MSCs into chondrocytes.