Low frequence pulsed electromagnetic fields induce chondrocyte-like cells differentiation of rat bone marrow-derived mesenchymal stem cells in vitro.
Institute of Biomedical Engineering, West China College of Preclinical Medicine and Forensic Medicine, Sichuan University, Chengdu 610041, China.
Mesenchymal stem cells (MSCs) are multipotent stem cells that differentiate into a variety of cell types. Low frequency pulsed electromagnetic fields (LFPEMFs) therapy can causes biochemical changes at the cellular level to accelerate tissue repair in mammals. So, we tested the hypothesis that LFPEMFs can promote chondrogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs) in vitro. The rBMSCs were isolated by adherence method and the third-generation of the rBMSCs were randomly divided into LFPEMFs groups, chondrocyte-induced group and control group. LFPEMFs groups with complete medium were exposed to 50Hz, 1mT PEMFs for 30 min every day, lasting for 10, 15 and 20 d, respectively. Chondrocyte-induced group were treated with chondrogenic media, while control groups were only cultured with complete medium. The mRNA expressions of type II-collagen (Col II) and aggrecan were determined by Real-time fluorescent quantitation PCR. The protein expression of Col II and aggrecan were detected with toluidine blue stain or immunocytochemical stain, respectively. The result showed that the mRNA and protein expression level of Col-II and aggrecan were significantly higher in the LFPEMFs group or chondrocyte-induced group, compared to the control group. It suggest that LFPEMFs could contribute to rBMSCs to differentiate into chondrogenic differentiation in vitro.
Int J Mol Med. 2012 May;29(5):823-31. doi: 10.3892/ijmm.2012.919. Epub 2012 Feb 16.
Millimeter wave treatment promotes chondrocyte proliferation via G1/S cell cycle transition.
Academy of Integrative Medicine, Fujian University of Traditional Chinese Medicine, Fuzhou 350108, P.R. China.
Millimeter waves, high-frequency electromagnetic waves, can effectively alleviate the clinical symptoms in osteoarthritis patients, as a non-pharmaceutical and non-invasive physical therapy regimen. However, the molecular mechanisms of the therapeutic effects of millimeter wave treatment are not well understood. In the present study, the effect of millimeter waves on the G1/S cell cycle progression in chondrocytes and the underlying mechanism was investigated. Chondrocytes isolated from the knee of SD rats were cultured and identified using toluidine blue staining. The second generation chondrocytes were collected and stimulated with or without millimeter waves for 48 h. Chondrocyte viability was analyzed using the MTT assay. The cell cycle distribution of chondrocytes was analyzed by flow cytometry. mRNA and protein expression levels of cyclin D1, cyclin-dependent kinases 4 and 6 (CDK4 and CDK6) and p21 were detected using real-time PCR and western blotting, respectively. Millimeter wave stimulation was found to significantly enhance chondrocyte viability. Moreover, the percentage of chondrocytes in the G0/G1 phase was significantly decreased, whereas that in the S phase was significantly increased. In addition, following millimeter wave treatment, cyclin D1, CDK4 and CDK6 expression was significantly upregulated, whereas p21 expression was significantly downregulated. The results indicate that millimeter wave treatment promotes chondrocyte proliferation via cell cycle progression.
Millimeter wave treatment promotes chondrocyte proliferation by upregulating the expression of cyclin-dependent kinase 2 and cyclin A.
Fujian University of Traditional Chinese Medicine, University Town, Minhou Shangjie, Fujian 350108, PR China.
We investigated the effects of millimeter wave treatment on the expression of the cell cycle regulating proteins cyclin-dependent kinase 2 (CDK2) and cyclin A in chondrocytes. Knee articular cartilage from SD rats was used to establish cultured primary chondrocytes. After identification using toluidine blue staining, passage 2 chondrocytes were randomly divided into different groups and treated with nocodazole or millimeter wave. The RNA expression of CDK2 and cyclin A was measured using RT-PCR, and their protein levels were detected by Western blotting. Cell cycle analysis showed that nocodazole treatment significantly increased the number of G0/G1 and G2/M stage chondrocytes and decreased the amount of S phase cells. In contrast, millimeter wave treatment significantly decreased the number of G0/G1 and G2/M chondrocytes and increased the number of S phase cells. The mRNA and protein levels of CDK2 and cyclin A consistently demonstrated a reverse trend, with the lowest levels in the chondrocytes treated with nocodazole. The expression of CDK2 and cyclin A was higher in chondrocytes receiving millimeter wave treatment than in untreated cells. In conclusion, millimeter wave treatment induces CDK2 and cyclin A expression, accelerates S-phase entry and G2/M transition and promotes chondrocyte cell cycle progression.