title: Propofol inhibits gap junctions by attenuating sevoflurane-induced cytotoxicity against rat liver cells in vitro.
abstract: BACKGROUND
  Liver abnormalities are seen in a small proportion of patients following anaesthesia with sevoflurane.
  
  
  OBJECTIVE
  To investigate whether the cytotoxicity of sevoflurane against rat liver cells was mediated by gap junction intercellular communications, and the effect of propofol on sevoflurane-induced cytotoxicity.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  The study was carried out in the central laboratory of The Third Affiliated Hospital, Sun Yat-sen University.
  BRL-3A rat liver cells.
  
  
  METHODS
  Immortal rat liver cells BRL-3A were grown at low and high density. Colony-forming assays were performed to determine clonogenic growth of these cells. To investigate the effect of oleamide and propofol on gap junction function, we measured fluorescence transmission between cells using parachute dye-coupling assays. Immunoblotting assays were performed to determine connexin32 and connexin43 expression.
  
  
  RESULTS
  Our colony formation assays revealed that, in low-density culture, sevoflurane caused no apparent inhibition of clonogenic growth of BRL-3A cells. In high-density culture, 2.2 to 4.4% sevoflurane markedly inhibited clonogenic growth of BRL-3A cells with 67.6 (0.34)% and 61.2 (0.17)% of the cells being viable, respectively (P = 0.003 vs. low-density culture), suggesting cell density dependency of sevoflurane-induced cytotoxicity. Our colony formation assays revealed that propofol markedly attenuated the suppression by sevoflurane of the clonogenic growth of BRL-3A cells (viability: propofol and sevoflurane, 91.5 (0.014)% vs. sevoflurane, 56.6 (0.019)%; P <0.01). Blocking gap junctions with 10 μmol l oleamide significantly attenuated 4.4% sevoflurane-induced suppression with a viability of 83.6 ± 0.138% (oleamide and sevoflurane vs. sevoflurane, P < 0.01). Immunoblotting assays further showed that propofol (3.2 μg ml) markedly reduced CX32 levels and significantly inhibited gap junctional intercellular communications as revealed by parachute dye-coupling assays. Values are mean (SD).
  
  
  CONCLUSIONS
  This study provides the first direct evidence that sevoflurane-induced cytotoxicity, which is mediated through gap junctions, is attenuated by propofol, possibly by its action on Cx32 homomeric or heteromeric complexes.
authors.affiliation: From the Department of Anaesthesiology, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China.
authors.forename: Fei
authors.initials: F
authors.lastname: Huang
authors.forename: Shangrong
authors.initials: S
authors.lastname: Li
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Gan
authors.forename: Ren
authors.initials: R
authors.lastname: Wang
authors.forename: Zhonggang
authors.initials: Z
authors.lastname: Chen
mesh_terms: D018685:Anesthetics, Inhalation / Q000633:toxicity; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D056486:Chemical and Drug Induced Liver Injury / Q000473:pathology / Q000517:prevention & control*; D018031:Connexin 43 / Q000235:genetics; D017630:Connexins / Q000235:genetics; D017629:Gap Junctions / Q000187:drug effects*; D008099:Liver / Q000187:drug effects / Q000473:pathology; D008738:Methyl Ethers / Q000633:toxicity*; D015742:Propofol / Q000494:pharmacology*; D051381:Rats; D000077149:Sevoflurane; D000097002:Gap Junction beta-1 Protein
chemical_list: D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D018031:Connexin 43; D017630:Connexins; D008738:Methyl Ethers; D015742:Propofol; D000077149:Sevoflurane; D000097002:Gap Junction beta-1 Protein