Construction of Eukaryotic Expression Plasmid of hTGF-β3 and Its Inducing Effect on Differentiation of Precartilaginous Stem Cells into Chondroblasts

This study examined the construction of eukaryotic expression plasmid of human transforming growth factor-β3（hTGF-β3） and its inducing effect on the differentiation of precartilaginous stem cells（PSCs） into chondroblasts.hTGF-β3 gene was amplified by using polymerase chain reaction（PCR） and then inserted into the eukaryotic expression plasmid pcDNA3.1 to construct the eukaryotic expression plasmid pcDNA3.1（＋）-hTGF-β3.Rat PSCs were isolated and purified by employing an immunomagnetic cell sorting system.pcDNA3.1（＋）-hTGF-β3 was transfected into purified PSCs with the use of linear polyamines.The expression of TGF-β3 and cartilage-specific extracellular matrix（ECM） components was detected after transfection by real-time quantitative PCR,ELISA,immunochemistry and Western blotting,respectively.The results showed that the eukaryotic expression plasmid pcDNA3.1（＋）-hTGF-β3 was successfully established as identified by enzyme digestion and DNA sequencing.Real-time quantitative PCR and ELISA revealed that hTGF-β3 was strongly expressed in pcDNA3.1（＋）-hTGF-β3-transfected PSCs.Real-time quantitative PCR,immunochemistry and Western blotting showed that the cartilage-specific ECM markers,i.e.,cartilage oligomeric matrix protein（COMP）,Aggrecan,collagen type Ⅹ and Ⅱ were intensely expressed in the pcDNA3.1（＋）-hTGF-β3transfected cells.It was concluded that hTGF-β3 could be stably expressed in pcDNA3.1（＋）-hTGFβ3-transfected PSCs and induce the differentiation of PSCs into chondroblasts.