Effect Of Platelet Lysate On Inducing Human Umbilical Cord Derived Mesenchymal Stem Cells Into Chondrocytes In Vitro

Objective:To study the effect of platelet lysate(PL) during the induction course from human umbilical cord derived mesenchymal stem cells(hUCMSCs) to chondrocytes in vitro.Methods:HUCMSCs were isolated by collagenase digestion. The surface markers of the cells were detected by flow cytometer. According to the different components of inductive medium we divided the study into the following three groups:Group A: H-DMEM medium,10%fetal bovine serum(FBS) and10%PL; Group B:H-DMEM medium,10%FBS,10ng/ml TGF-Bl,1×1O"’mol/L dexamethasone,50ug/ml vitamin C and1%Insulin-Transferrin-Selenium (ITS); Group C:H-DMEM medium,10%FBS,10ng/ml TGF-B1,1×10-1mol/L dexamethasone,50ug/ml vitamin C,1%ITS and10%PL. The hUCMSCs were induced in the mediums above by two weeks. Toluidine blue staining detected the secretion of chondrocyte matrix. Immunofluorescence were used to identify the existence of collagen Ⅱ. The expressions of aggrecan and collagen II were detected by semiquantitative RT-PCR. Results:Flow cytometer results showed that the hUCMSCs were negative for surface markers of hematopoietic cell CD34, CD45and HLA-DR, but were positive for surface markers of adhesion molecule and MSCs CD44, CD105and CD146. Toluidine blue staining and immunofluorescence proved positive in group C, weak positive in group B and negative in group A. Semiquantitative RT-PCR showed expressions of aggrecan and collagen Ⅱ in mRNA level. There were expressions in group B and C, but no expression in group A. showing significant difference(P<0.05). Conclusion:Only10%PL can’t induce hUCMSCs into chondrocytes, but it can be a supplement to the induced mediums in the procedure. PL can improve hUCMSCs differentiating into chondrocytes obviously in vitro. This study provides new available conditions for constructing tissue-engineered cartilage.