title: ClC chloride channels in tooth germ and odontoblast-like MDPC-23 cells.
abstract: OBJECTIVE
  To detect expression of ClC chloride channel mRNA in tooth germ and odontoblasts, and explore the affect of chloride channel function on cell proliferation and cell cycle.
  
  
  METHODS
  We extracted total RNA of tooth germ from newborn C57BL mice and mouse odontoblast-like cells (MDPC-23), then detected mRNA expression of chloride channel genes Clcn1-7 with RT-PCR. We used chloride channel blocker 5-nitro-2-(3- phenylpropylamino)benzoic acid (NPPB) to interfere with chloride channel function of MDPC-23 cells. Cell proliferation rate and cell cycle were detected with MTT assay and flow cytometry, respectively. Student's t-test was used to determine statistical significance between control and treatment groups.
  
  
  RESULTS
  The mRNA of Clcn1-7 chloride channel genes was expressed in tooth germ of newborn mice. Clcn3, Clcn5 and Clcn7 mRNAs were expressed in MDPC-23 cells. NPPB slowed down the proliferation rate of MDPC-23 cells from day 2 to day 4 (P<0.01), and also changed the proportion of cell cycle phase. Comparing to the control, the proportion of G2/M phase cells reduced from 3.93+/-2.62% to 0.54+/-0.25% (P<0.05). The ratio of G1/G2 increased from 1.86+/-0.01 to 1.95+/-0.02 (P<0.05).
  
  
  CONCLUSIONS
  There is abundant chloride channel gene expression in tooth germ. Some of these chloride channels may regulate tooth development through effects on cell proliferation and cell cycle signal pathway.
authors.affiliation: Department of Oral Biology, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, Shaanxi 710032, PR China.
authors.forename: Jin
authors.initials: J
authors.lastname: Hou
authors.forename: Zhenqiang
authors.initials: Z
authors.lastname: Situ
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Duan
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002453:Cell Cycle / Q000187:drug effects* / Q000235:genetics; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D005434:Flow Cytometry; D015870:Gene Expression / Q000187:drug effects; D005786:Gene Expression Regulation; D051379:Mice; D009804:Odontoblasts / Q000378:metabolism*; D020005:Propanols / Q000008:administration & dosage; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014083:Tooth Germ / Q000187:drug effects / Q000378:metabolism*
chemical_list: D018118:Chloride Channels; D020005:Propanols; D012333:RNA, Messenger; C439395:1-phenylpropanol