title: [Effects of endotoxin/lipopolysaccharide on proliferation and apoptosis of human umbilical cord mesenchymal stem cells].
abstract: OBJECTIVE
  To investigate the effects of different concentrations of lipopolysaccharide (LPS) on proliferation and apoptosis of human umbilical cord mesenchymal stem cells (hUCMSCs) in vitro, and to explore their possible mechanism.
  
  
  METHODS
  hUCMSCs from umbilical cord tissue of full-term healthy fetus delivered by caesarean section were isolated and cultured in vitro using tissue attachment method. The 3rd passage hUCMSCs were used in the study. Cells were divided into groups A, B, C, D, and E, which were treated with DMEM/F12 medium containing 0, 0.1, 1.0, 10.0, and 100.0 µg/mL of LPS respectively. In groups B, C, D, and E, methyl-thiazole-tetrazolium assay was used to detect proliferative activity of hUCMSCs at post treatment hour (PTH) 12, 24, and 48 (denoted as absorption value), with 5 samples in each group at each time point; apoptosis of hUCMSCs at PBH 24 was identified with acridine orange-ethidium bromide (AO-EB) staining, with 4 samples in each group; apoptotic rate of hUCMSCs was determined by flow cytometer, with 5 samples in each group. Above-mentioned indexes were determined in group A at the same time points. Data were processed with analysis of variance and LSD- t test.
  
  
  RESULTS
  (1) There was no statistically significant difference in proliferative activity of hUCMSCs at PTH 12 among groups A, B, C, D, and E (with t values from -1.67 to 1.33, P values above 0.05). Compared with that of group A, proliferative activity of hUCMSCs was increased in groups B, C, and D at PTH 24 and 48 (with t values from -13.42 to 17.34, P < 0.05 or P < 0.01), especially so in group C. Proliferative activity of hUCMSCs was lower in group E at PTH 24 and 48 than in group A (with t values respectively 8.64 and 17.34, P values below 0.01). (2) Obvious apoptosis of hUCMSCs was observed in group E but not in the other 4 groups with AO-EB staining. (3) Apoptosis rates of hUCMSCs in groups A, B, C, D, and E were respectively (3.1 ± 0.6)%, (2.6 ± 0.7)%, (2.9 ± 0.8)%, (3.1 ± 0.4)%, (25.1 ± 2.7)% (F = 272.19, P < 0.01). Apoptotic rate of hUCMSCs in group B, C, or D was respectively close to that in group A (with t values respectively 1.22, 0.57, -0.14, P values above 0.05), but it was higher in group E than in group A (t = -17.63, P < 0.01).
  
  
  CONCLUSIONS
  hUCMSCs proliferation may be promoted by low concentration of LPS. hUCMSCs proliferation is inhibited or induced to apoptosis along with the increase in concentration of LPS, and it may be related to activation of different major molecular signaling pathways by different concentrations of LPS.
authors.affiliation: Burns Institute, the First Hospital Affiliated to the PLA General Hospital, Beijing 100048, China.
authors.forename: Yusen
authors.initials: Y
authors.lastname: Hou
authors.affiliation: Burns Institute, the First Hospital Affiliated to the PLA General Hospital, Beijing 100048, China. Email: cjk304@126.
authors.forename: Jiake
authors.initials: J
authors.lastname: Chai
authors.affiliation: Burns Institute, the First Hospital Affiliated to the PLA General Hospital, Beijing 100048, China.
authors.forename: Lingying
authors.initials: L
authors.lastname: Liu
authors.affiliation: Burns Institute, the First Hospital Affiliated to the PLA General Hospital, Beijing 100048, China.
authors.forename: Hongjie
authors.initials: H
authors.lastname: Duan
authors.affiliation: Burns Institute, the First Hospital Affiliated to the PLA General Hospital, Beijing 100048, China.
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Burns Institute, the First Hospital Affiliated to the PLA General Hospital, Beijing 100048, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Hu
authors.affiliation: Burns Institute, the First Hospital Affiliated to the PLA General Hospital, Beijing 100048, China.
authors.forename: Wanli
authors.initials: W
authors.lastname: Chu
authors.affiliation: Burns Institute, the First Hospital Affiliated to the PLA General Hospital, Beijing 100048, China.
authors.forename: Yihe
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Burns Institute, the First Hospital Affiliated to the PLA General Hospital, Beijing 100048, China.
authors.forename: Hongmin
authors.initials: H
authors.lastname: Luo
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D049109:Cell Proliferation; D004731:Endotoxins / Q000009:adverse effects*; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008565:Membrane Proteins; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects*; D015398:Signal Transduction; D014470:Umbilical Cord / Q000166:cytology
chemical_list: D004731:Endotoxins; D008070:Lipopolysaccharides; D008565:Membrane Proteins; C025357:endotoxin binding proteins