Background and Aims: The current study was conducted to compare the expression levels of collagen type Π and X during chondrogenesis of human adipose-derived mesenchymal stem cells (hADMSCs) pellet and micromass cultures. 
Materials and Methods: Extracted hADMSCs were cultured until three passages and then transferred to pellet and micromass cultures in the experimental groups of day 7 and day14. For pellet and micromass cultures, aliquots of 5×10⁵ cells/ml were centrifuged and respectively cultured in the conical tubes and droplets (12.5 µl) of the 24-well plates containing chondrogenic medium. Realtime-polymerase chain reaction technique was performed for gene expression levels.
Results: Increased expression of collagen type Π was shown in micromass day14 compared to micromass day 7, pellet day 14 (p<0.01) and pellet day 7 (p<0.001). Also, an increased expression of collagen type Π was seen in micromass day 7 and pellet day 14 compared to pellet day 7 (p< 0.05). Expression of collagen type X increased in pellet day 14 compared to micromass on days 7 and 14 (p<0.001, p<0.01) and pellet day14 compared to pellet day7 (p< 0.05). An increased expression of collagen type X was shown in pellet day 7 compared to micromass on days 7 and 14 (p<0.05).
Conclusions: According to the results, higher expression of collagen type Π and lower expression of collagen type X in micromass cultures that are prepared by cell suspension play a better role during cellular condensation that leads to the formation of large nodules exhibiting cartilage-like morphology, suggests a higher efficiency for micromass cultures.