| Background: Human bone marrow mesenchymal stem cell exists in various tissues such as bone,fat,skin,it has self-renewal capacity and multilineage differentiative potential.It is easy to be isolated in vitro and can be induced into all kinds of tissue cells through specific methods,so as to achieve the repair of bone and cartilage.Therefore,mesenchymal stem cell can be used as ideal seed cells in tissue engineering,and is likely to be used in clinic for the treatment of necrosis of femoral head and other orthopedic diseases.Lithium is considered to be one of the most effective drugs for the the treatment of depression and hematopoietic system diseases.Although lithium can stabilize the manic mood and has a great role for antidepressant treatment,there is no direct evidence that lithium can cure orthopedic diseases such as avascular necrosis of the femoral head.A large number of studies have shown that lithium can activate Wnt/?-catenin signaling pathway which plays a pivotal role for bone marrow mesenchymal stem cellaular proliferation,cellular growth and normal stem cellular differentiation.Lithium can regulate bone marrow mesenchymal stem cellular proliferation and differentiation,so as to promote the self repair of bone necrosis disease.Objective:To study the effects of lithium on the adipogenicdifferentiation and the osteogenic differentiation of bone marrow mesenchymal stem cells.Methods;BMSC are derived from patients with hip joint replacement of the femoral head.The cells were divided into two groups,respectively as the experimental group and the control group,in the experimental group,cellular adipogenic culture medium was added with different concentration of lithium chloride,three weeks later,we observed the effect of adipogenic differentiation and the osteogenic differentiation by oil red staining and alizarin red staining.Then we used Western blot and immunofluorescence assay to detect related osteogenic protein and used RT-PCR to detect gene expression level.We compared the difference between the two groups,then we used quercetin to block Wnt/?-catenin signaling pathway and repeated experiments,and then compared the results again.Results:Flow cytometry method: bone marrow mesenchymal stem cellular positive cell surface markers CD44 reached 95.6% positive rate,CD90 reached 99%positive rate,CD105 reached 77.7% positive rate.At the same time,blood stem cell surface markers CD34,CD45's expression rate were less than1%.Chemical staining;The number of lipid droplets in the experimental group was significantly lower than that in the blank group.The number of calcium nodules in the experimental group was significantly higher than that in the blank group.RT-PCR:PPAR?,LPL,adipoQ genetic expression were inhibited.OCN,RUNX2,ALP genetic expression were promotedImmunofluorescence:In the experimental group,the expression of LPL protein was inhibited after 21 days of adipogenic differentiation.OCNprotein expression increased after 21 days of osteogenic differentiation.Western blot: After 21 days adipogenic differentiation,the expression of LPL was inhibited.After 21 days osteogenic differentiation,the expression of ALP,RUNX2 and OCN was promoted.Wnt/?-Catenin signal pathway was up-regulated in the experimental group,and the effect was time and dose related.Wnt/?-Catenin pathway inhibition abolishes the effects of lithium.Conclusion: Lithium inhibits adipogenic differentiation and promotes osteogenic differentiation of Human Bone Marrow Mesenchymal Stem Cells in vitro by stimulating Wnt/?-catenin signaling... |
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