| Summary: | 碩士 === 高雄醫學大學 === 生物化學研究所 === 97 === Mesenchymal stem cells (MSCs), the primitive progenitors from bone marrow, adipose tissue and various adult tissues have self-renew ability and multilineage potential to differentiate into osteoblasts, adipocytes, chondrocytes, muscle cells, neurons, hepatocytes and insulin-producing β cells. Because of their specificity and functional properties MSCs can applied to repair injurious tissues and treat degenerate diseases such as osteoporosis, osteoarthritis and neurodegenerative disease.
Previous studies indicated trace elements play important roles in bone formation and balance. Manganese ( Mn ) participates in regulating bone mineralization. Zinc ( Zn ) is essential for bone formation and tissue repair. Lack of selenium ( Se ) may increase risk of knee osteoarthritis. Cooper ( Cu ) deficiency reduces collagen formation. Therefore, trace elements are essential in bone development and maturation.
However, trace elements how effect cell growth and differentiation of mesenchymal stem cells and the regulatory mechanisms have not been full elucidated. This study used manganese chloride ( MnCl2 ), zinc sulfate ( ZnSO4 ), sodium selenite ( Na2SeO3 ) and cupric sulfate ( CuSO4 ) and investigated the effects and molecular mechanisms of these trace elements on cell growth and osteogenic differentiation of bone marrow stromal cell line M2-10B4.
Our results revealed that MSCs treated with low dose ( 0.01 mM ) MnCl2 , ZnSO4 , CuSO4 and ( 0.03 mM ) Na2SeO3 could maintain cell proliferation, but high dose ( 0.1 mM ) MnCl2, ZnSO4, ( 0.15 mM ) Na2SeO3 and ( 0.2 mM ) CuSO4 inhibited cell growth. Cell cycle analysis indicated MSCs at low dose of MnCl2, ZnSO4, CuSO4 and Na2SeO3 had unapparent effect for 24 and 48 hours, but at high dose all increased G2/M phase arrest following 24 and 48 hours. Results established M2-10B4 cells in excess of trace elements inhibited cell replication and mitotic capabilities. DNA ladder assay showed M2-10B4 cells exposure to excess trace elements promoted G2/M phase arrest but not apoptosis. The expressions of chk2, Wee1, cdc25c and cdc2 reflected possible function of higher MnCl2, ZnSO4 and CuSO4 dose in supporting the G2/M phase arrest. In addition, the mRNA expression of Runx2 ( Runt-related transcription factor 2 ) and ALP ( alkaline phosphatase ) further elucidated their osteogenic differentiation potential. Our results demonstrated that higher trace elements inhibited MSCs to differentiate into osteoblasts.
Our study indicated appropriate intake of trace elements might be helpful in keeping activities of stromal stem cells. Conversely, excessive trace elements resisted cell growth and reduced MSCs osteogenic abilities. Therefore, it is important to take suitable trace elements that will improve healthy and prevent diseases.
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