title: [In vitro studies on the growth and proliferation characteristics of rat bone mesenchymal stem cells].
abstract: OBJECTIVE
  This study was to investigate the growth and proliferation characteristics of rat bone mesenchymal stem cells (BMSCs) isolated by the method of whole bone marrow culture and to explore the effect of cell inoculation density and incubation period on cell proliferation, with an aim to provide multipotential seed cells for preventing from degenerative disease.
  
  
  METHODS
  Bone mesenchymal stem cells were isolated by the method of whole bone marrow culture and then cultured in vitro. The cell morphologic features were observed by inverted microscope. The cell surface antigens were identified by flow cytometry. The effect of cell inoculation density and culture period on cell growth and proliferation was explored by analyzing the characteristics of a ten-day cell growth curve in 96-well plates.
  
  
  RESULTS
  Flow cytometry results showed the detection rates for CD29, CD34 and CD45 were 97.68% (7607/7788), 7.93% (661/8340) and 2.76% (215/7788) respectively, which was consistent with the expression characteristics of BMSCs surface antigens. BMSCs became uniform after three cell passages, existing in a typical shape of whirlpool or radial colony. The senescent cells started to appear at 7(th) passage, and more senescent cells were found at 10(th) passage. The growth curve for moderate inoculation density was typically S-shaped. Lag phase was found during the first two days, and logarithm growth phase was in the following three days. Plateau phase started from the 6(th) day and cell numbers decreased slightly from the 8(th) day.
  
  
  CONCLUSIONS
  The whole bone marrow culture is an effective way to obtain BMSCs. A moderate inoculation density was more advantageous to cell proliferation, by which more seed cells could be obtained.
authors.affiliation: Department of Endocrinology, the Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China. zhshuxc@163.com
authors.forename: Xiao-chun
authors.initials: XC
authors.lastname: Shu
authors.forename: Dan-hua
authors.initials: DH
authors.lastname: Zhu
authors.forename: Jun-jing
authors.initials: JJ
authors.lastname: Liu
authors.forename: Dai-chan
authors.initials: DC
authors.lastname: Yin
authors.forename: Tian-jiao
authors.initials: TJ
authors.lastname: Pang
authors.forename: Hong-yun
authors.initials: HY
authors.lastname: Lu
authors.forename: Liao
authors.initials: L
authors.lastname: Sun
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology*; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D005434:Flow Cytometry; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051381:Rats; D017207:Rats, Sprague-Dawley