title: [Effect of N,N-dimethylformamide on calcium homeostasis and the calpain gene expression in human hepatocytes].
abstract: OBJECTIVE
  To investigate the effect of N,N-dimethylformamide (DMF) on calcium homeostasis and calpain I and II gene expression in human hepatocytes (HL-7702).
  
  
  METHODS
  HL-7702 cells were exposed to different concentrations of DMF (10, 25, 50, 100, or 200 mmol/L); other HL-7702 cells, which were used as a control group, were exposed to the equal volume of DMEM; the intracellular Ca(2+) concentration was monitored using the calcium fluorescent probe (fluo-3/AM). After 24-h exposure to DMF (10, 25, 50, 100, 150, or 200 mmol/L), the morphology of hepatocytes was observed under an inverted phase contrast microscope, and the cell viability was measured by MTT assay. After 24-h exposure to DMF (10, 25, 50, 100, or 150 mmol/L), the mRNA expression levels of calpain I and II in hepatocytes were measured by real-time quantitative PCR.
  
  
  RESULTS
  There were significant differences in cell viability among different exposure groups (P < 0.01); the 50, 100, 150, and 200 mmol/L DMF exposure groups had a significantly lower cell viability than the control group (P < 0.05). Under the inverted phase contrast microscope, HL-7702 cells gradually lost the original shape, with swelling and shrinking, as the dose of DMF increased, and those treated with 150 mmol/L DMF even became round and floated. The fluorescence density of fluo-3 in hepatocytes increased as the dose of DMF rose, demonstrating a dose-response relationship, and there were significant differences among these exposure groups (P < 0.05). There were significant differences in mRNA expression levels of calpain I and II among these exposure groups (P < 0.01), and the expression increased as the dose of DMF rose; but DMF did not promote the mRNA expression of calpain I at a concentration of 150 mmol/L.
  
  
  CONCLUSIONS
  DMF can cause damage to hepatocytes, which is related to intracellular calcium increase and calpain mRNA increase.
authors.affiliation: Zhejiang Academy of Medical Sciences, Hangzhou, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Jun-qiang
authors.initials: JQ
authors.lastname: Chen
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.forename: Xiao-ming
authors.initials: XM
authors.lastname: Huang
authors.forename: Ling-fang
authors.initials: LF
authors.lastname: Feng
authors.forename: Zhen-yu
authors.initials: ZY
authors.lastname: Jia
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
mesh_terms: D002118:Calcium / Q000378:metabolism; D002154:Calpain / Q000378:metabolism*; D002460:Cell Line; D004126:Dimethylformamide / Q000494:pharmacology*; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism*; D006801:Humans
chemical_list: D004126:Dimethylformamide; D002154:Calpain; D002118:Calcium