[Objective]To study the differentiation of adipose-derived adult stem cells(ADASCs)into chondrocytes induced by TGF-?1 in the presence of different concentrations of serum in vitro.[Method]Adipose tissue-derived adult stem cells were isolated from rabbits subcutaneous adipose tissue using enzymatic digestion.The adipose tissue was minced and digested with collagenase type I,and the released cells were collected by density centrifugation and then placed in culture.After being passaged three times,ADASCs were induced to differentiate into chondrocytes by chondrogenic culture media containing 1% or 10% of FBS for 2 weeks.MTT,alkaline phosphatase toluidine blue staining and type Ⅱ collagen immunohistochemistry staining were then tested in both groups.Gray value was analyzed by Leica patho-image analysis system to observe if there was any difference in differentiative status between the two groups.[Result]MTT showed that the cells of 10% FBS group had higher proliferation activity than those of 1% FBS group(P