Abstract: BACKGROUND: Previous studies of the research group have found that icariin-containing serum can delay the progression of knee osteoarthritis, promote chondrocyte proliferation and stem cell cartilage differentiation in rats, but there is still a lack of sufficient basis for clinical application. 
OBJECTIVE: To investigate the repair effect of icariin-containing serum on lipopolysaccharide-induced inflammatory damage of human chondrocytes. 
METHODS: The effect of icariin-containing serum on chondrocyte viability was detected by cell counting kit-8 method, and the optimal volume fraction and time of icariin-containing serum were screened. The cells were then divided into blank group, lipopolysaccharide group, icariin-containing serum group and lipopolysaccharide+icariin-containing serum group. After grouping, immunofluorescence was used to detect the secretion of type II collagen in chondrocytes in each group. Real-time PCR was used to detect the expression of related genes. 
RESULTS AND CONCLUSION: (1) Icariin-containing serum showed good biosafety characteristics for human chondrocytes, and the cell viability reached the highest level after 48 hours of intervention when the icariin-containing serum volume fraction was 15%, and the follow-up experiments were carried out according to the conditions. (2) Compared with the blank group, lipopolysaccharide significantly inhibited the expression of type II collagen in chondrocytes, while icariin-containing serum showed a positive mobilization effect, which could effectively promote the secretion of type II collagen in chondrocytes under normal and inflammatory conditions. (3) The mRNA expression of type II collagen and Aggrecan in chondrocytes decreased significantly under lipopolysaccharide stimulation, and the mRNA expression levels of matrix metalloproteinase 13 and a disintegrin-like and metalloproteinase with thrombospondin motifs-5 increased significantly. Icariin-containing serum promoted the mRNA expression of type II collagen in human chondrocytes under inflammatory conditions and reduced the mRNA expression of matrix metalloproteinase 13 and a disintegrin-like and metalloproteinase with thrombospondin motifs-5 in chondrocytes after lipopolysaccharide intervention. Therefore, these findings indicate that the icariin-containing serum has good safety for human chondrocytes and plays an important role in maintaining the normal physiological functions of chondrocytes, promoting the synthesis of extracellular matrix, and inhibiting the secretion of inflammatory factors.

中国组织工程研究杂志出版内容重点：干细胞；骨髓干细胞；造血干细胞；脂肪干细胞；肿瘤干细胞；胚胎干细胞；脐带脐血干细胞；干细胞诱导；干细胞分化；组织工程

Key words: cartilage injury, cartilage repair, knee osteoarthritis, icariin, icariin-containing serum, engineered tissue construction