[Oxysterol (3,5-cholestadien-7-one, 5 beta-cholestan-3-one, 5,24-cholestadien-3 beta-OL) induced cytotoxicity and apoptosis in gallbladder epithelial cells].
OBJECTIVE
Biliary epithelial cells are exposed to highly concentrated oxysterols. Therefore, oxysterols may play a role in pathogenesis of biliary tract diseases. We investigated the cytotoxic effect and apoptosis inducing effect of oxysterol on gallbladder epithelial cells.


METHODS
We studied the cytotoxic effect of 3,5- cholestadien-7-one, 5 beta-cholestan-3-one and 5,24-cholestadien-3 beta-OL which are identified in human bile and pigment gallstones on dog gallbladder epithelial cells (DGBE) and mouse gallbladder epithelial cells (MGBE). We used model bile to dissolve oxysterols as in vitro experiment and also used MTT, cell count, Diff-Quick stain, and flow cytometry to investigate cytotoxicity and apoptosis.


RESULTS
Oxysterols dissolved in model bile have cytotoxic effects in a dose dependent fashion. In oxysterol containing model bile, viable cells are 51% in 500 microM 5 beta-cholestan-3-one (cholesterol:oxysterol 50:50) and 47% in 5 mM 3,5-cholestadien-7-one (90:10) on MGBE, and are 129% and 38% in 500 microM (50:50) 3,5-cholestadien-7-one and 5 beta-cholestan-3-one on DGBE, and are 74% and 71.5% in 5 mM (90:10) 3,5-cholestadien-7-one and 5 beta-cholestan-3-one on DGBE, respectively. 500 microM (50:50) 3,5- cholestadien-7-one, 5 beta-cholestan-3-one, and 5,24-cholestadien-3 beta-OL treated on DGBE increase the apoptotic cell number as 22.0+/-8.8, 30.2+/-12.6, and 45.5+/-13.2%, respectively, compared with control (14.6+/-10.0%). 500 microM (50:50) 3,5-cholestadien-7-one, 5 beta-cholestan-3-one, and 5,24-cholestadien-3 beta-OL also affect the changes in cell cycles compared with the control.


CONCLUSIONS
We concluded that oxysterol containing model bile is useful as an in vitro experiment as model to analyze the effects of oxysterols on biliary epithelial cells and that adequate concentration of oxysterols can induce the cytotoxic effect and the apoptosis on gallbladder epithelial cells.
Choi
Ho Soon
HS
Department of Internal Medicine, Hanyang University College of Medicine, Seoul 133-791, Korea. choihs@hanyasng.ac.kr
Kim
Young Woog
YW
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001646:Bile / Q000737:chemistry; D002774:Cholestadienes / Q000633:toxicity*; D002775:Cholestadienols / Q000633:toxicity*; D002776:Cholestanes / Q000633:toxicity*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects*; D005704:Gallbladder / Q000166:cytology* / Q000187:drug effects; D066298:In Vitro Techniques; D051381:Rats
C500346:3,5-cholestadien-7-one; C500348:5,24-cholestadien-3beta-ol; C500347:5beta-cholestan-3-one; D002774:Cholestadienes; D002775:Cholestadienols; D002776:Cholestanes