Comparison of biological characteristics between bone marrow mesenchymal stem cells and anterior cruciate ligament derived mesenchymal stem cells in rats

Abstract

To compare the biological characteristics of bone marrow mesenchymal stem cells (BMSCs) and anterior cruciate ligament derived mesenchymal stem cells (ACL-MSCs) from rats in vitro. Ten male SPF-level BN rats, weighing 200-220 g, were selected to obtain anterior cruciate ligaments and bone marrows, and ACL-MSCs and BMSCs were isolated for passage culture respectively under sterile condition. The cell morphology was observed, and the cells at passage 3 were used to detect the surface markers of CD34, CD45, CD90, and CD29 by flow cytometry, the ability of cell proliferation by cell counting kit 8 (CCK-8), and colony formation ability by clone forming test. The mRNA levels of differentiation related genes [alkaline phosphatas (ALP), bone gamma-carboxyglutamate protein, runt related transcription factor 2, bone morphogenetic protein 2 (BMP-2), secreted phosphoprotein 1 (Spp1), collagen type II α1 (Col2α1), Aggrecan (Acan), Sox9, peroxisome proliferator activated receptor γ2 (PPARγ2), and CCAAT-enhancer-binding protein-α] were also determined by real-time fluorescent quantitative PCR. BMSCs and ACL-MSCs had similar morphology, adherent cells displaying long fusiform. The immunoprofile of ACL-MSCs and BMSCs at passage 3 was positive for CD29 and CD90 and was negative for CD45 and CD34. The absorbance ( A) value of ACL-MSCs (1.11±0.08) was significantly higher than that of BMSCs (0.78±0.05) ( t=3.599, P=0.023); the number of colonies of ACL-MSCs [(53.00±5.51)/hole] was significantly more than that of BMSCs [(30.67±4.84)/hole] ( t=3.045, P=0.038). The results of toluidine blue staining, alizarin red staining, and oil red O staining were positive in BMSCs and ACL-MSCs at 21 days after osteogenic, chondrogenic, and adipogenic induction. The mRNA expressions of BMP-2, Spp1, Col2α1, Acan, Sox9, and PPARγ2 in ACL-MSCs were significantly higher than those in BMSCs ( P<0.01). The proliferation potential of ACL-MSCs is greater than that of BMSCs, and the former is apt to differentiate into chondrocytes. ACL-MSCs are promising cells to promote tendon-bone healing.