Effect of age on rat bone marrow mesenchymal stem cell growth characteristics and differentiation potency / 中国组织工程研究

ABSTRACT

BACKGROUND:Previous research has shown that stem cells at different age stages had various proliferation and differentiation in vitro.Therefore,biological characteristics of bone marrow-derived mesenchymal stem cells at different age stages play a key role in evaluating differentiation into myocardial cells and determining proliferation and differentiation parameters in vitro.OBJECTIVE:To compare in vitro proliferation,surface marking,and differentiation into myocardial cells of bone marrow-derived mesenchymal stem cells from different aged rats.DESIGN,TIME AND SETTING:An in vitro contrast cytological observation was performed at the Laboratory of Biochemistry and Molecular Biology,Shanxi Medical University from May 2008 to May 2009.MATERIALS:A total of 15 healthy male Wistar rats were divided into three groups:1-month-old,3-month-old,and 12-month-old groups,with 5 rats in each group.METHODS:Bone marrow-derived mesenchymal stem cells were cultured using adherence screening method.At the third passage,cells differentiated into myocardium-like cells by the induction of 5-azacytidine.MAIN OUTCOME MEASURES:Cell proliferation was observed using MTT;cell surface marking was detected using flow cytometry;cardiac-specific myosin heavy chain mRNA expression was measured using RT-PCR.RESULTS:Bone marrow-derived mesenchymal stem cells were adherent in each group,and the proliferation curve was similar to each other.Under the same culture condition,the proliferation in the 1-month-old and 3-month-old groups was faster than 12-month-old group (F=28.71,P ＜ 0.05).The third-passage cells strongly expressed CD44 and CD71 but weakly expressed CD34 and CD45.At 2 weeks after 5-azacytidine induction,cardiac-specific myosin heavy chain mRNA was observed in all groups;however,the cardiac-specific myosin heavy chain mRNA expression in both 1-month-old and 3-month-old groups was significantly greater than 12-month-old group (t=5.140,2.827,P ＜ 0.05).CONCLUSION:With the age increasing of rats,proliferation,survival time,and differentiation of bone marrow-derived mesenchymal stem cells were weakened.