Differential Expression Of Cart-1 And Mmp3 In MSCs And Chondrocytes

Background and Objective: Cartilage tissue engineering refers to synthesis normal cartilage with chondrocytes and extracellular matrix. Tissue engineering research include stem cell, growth factor and frame materials. It had proved that MSCs (mesenchymal stem cells) were perfect ones in cartilage tissue engineering. Growth factors were the most important ones to determine MSCs differentiation. The previous studying of our group screened differentially expressed genes between SD rat bone mesenchymal stem cell , hyaline chondrocytes and elastic chondrocytes. It suggested the expression of Cart-1 (cartilage homeo protein 1) and Mmp3 (matrix metallopeptidase 3) in chondrocytes was higher than that in MSCs. It maybe the key gene of inducing MSCs into chondrocytes. In the present study , we validate the differential expression of Cart-1 and Mmp3 in MSCs and chondrocytes by western blot assy. It may provide thesis foundation in accurately choosing biology factors that to induce MSCs into chondrocytes.Methods: SD rat MSCs were purified with the density gradient centrifugation. SD rat elastic chondrocytes and hyaline chondrocytes were acquired from SD rat auricular cartilage and costal cartilage by enzyme digestion. Total protein was extracted from the cells of 2nd -3rd, and then apply western blotting assay to observe the expression of Cart-1 and Mmp3.Results:1. MSCs can be isolated by density gradient centrifugation and attachment method. In shape it showed spindle, and in phenotype it met the characteristics of MSCs.2. Western blot analysis: (1) the expression of Cart-1 in hyaline chondrocytes was higher than that in MSCs(P<0.01) ,the expression of Cart-1 in elastic chondrocytes was higher than that in MSCs(P<0.01),there was no differences between Cart-1 in hyaline chondrocytes and elastic chondrocytes.(2) the expression of Mmp3 in hyaline chondrocytes was higher than that in MSCs(P<0.01) ,the expression of Mmp3 in elastic chondrocytes was higher than that in MSCs(P<0.01), the expression of Mmp3 in elastic chondrocytes was higher than that of in hyaline chondrocytes.(P<0.01).Conclusion:1. Density gradient centrifugation combined with attachment method can be used to isolate and differentiate MSCs of rat.2. The expression of Cart-1 is unanimous at protein level and gene level. The high expression of Cart-1 in chondrocytes indicates that it will be one of the important biological factors which is able to induce the differentiation of MSCs into chondrocytes.3.The high expression of Mmp3 in elastic chondrocytes maybe prove that Mmp3 will be one of the important biological factors to induce MSCs into elastic chondrocytes.