RESEARCH ARTICLE Culture Temperature Affects Human Chondrocyte Messenger RNA Expression in Monolayer and Pellet Culture Systems

Cell-based therapy has been explored for articular cartilage regeneration. Autologous chon-drocyte implantation is a promising cell-based technique for repairing articular cartilage de-fects. However, there are several issues such as chondrocyte de-differentiation. While numerous studies have been designed to overcome some of these issues, only a few have focused on the thermal environment that can affect chondrocyte metabolism and pheno-type. In this study, the effects of different culture temperatures on human chondrocyte metabolism- and phenotype-related gene expression were investigated in 2D and 3D envi-ronments. Human chondrocytes were cultured in a monolayer or in a pellet culture system at three different culture temperatures (32°C, 37°C, and 41°C) for 3 days. The results showed that the total RNA level, normalized to the threshold cycle value of internal refer-ence genes, was higher at lower temperatures in both culture systems. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and citrate synthase (CS), which are involved in gly-colysis and the citric acid cycle, respectively, were expressed at similar levels at 32°C and 37°C in pellet cultures, but the levels were significantly lower at 41°C. Expression of th