title: PCB 77 action in ovary cells--toxic effects, apoptosis induction and cell cycle analysis.
abstract: BACKGROUND
  PCB 77 (3,3',4,4'-tetrachlorobiphenyl), a non-ortho congener with planar configuration, has been identified as potential endocrine disrupter capable to increase the risk of reproductive and developmental failure.
  
  
  OBJECTIVE
  In the present study, in vitro PCB 77 toxic potential, apoptosis induction and cell cycle alterations were investigated to reveal direct toxic effects on ovarian cells.
  
  
  METHODS
  Chinese Hamster Ovary (CHO-K1) cell line was selected as a model system and decreased cell viability was confirmed by application of four bioassays. Cellular morphology and quantitative analysis of apoptotic, necrotic and viable cells were determined with fluorescent microscopy and cell cycle phase distributions by measuring DNA content using flow cytometry.
  
  
  RESULTS
  We have indicated Trypan blue exclusion assay as the most sensitive for quantifying cytotoxicity of PCB 77 in terms of IC50 values, while the results obtained by other methods pointed to a possible localized effect on the lysosomes/endosomes (Neutral red), compromised intracellular metabolic processes (MTT) and possible interferation with the rate of protein synthesis (Kenacid blue). The loss of cell viability, as a consequence of treatment with 10-100 μM PCB 77, fundamentally was due to induction of apoptosis with observed common series of specific morphological changes characteristic to apoptotic phenomenon. The level of alterations of normal cell cycle progression was low without significant changes at analyzed time intervals.
  
  
  CONCLUSIONS
  These results indicate toxic outcomes of PCB 77 at ovarian cellular level with regard to potential direct adverse effects to female reproductive system.
authors.affiliation: a Laboratory for Toxicology, Faculty of Food Technology and Biotechnology , University of Zagreb , Zagreb , Croatia .
authors.forename: Teuta
authors.initials: T
authors.lastname: Murati
authors.forename: Branimir
authors.initials: B
authors.lastname: Šimić
authors.forename: Anamaria
authors.initials: A
authors.lastname: Brozovic
authors.forename: Jasna
authors.initials: J
authors.lastname: Kniewald
authors.forename: Adrijana
authors.initials: A
authors.lastname: Miletić Gospić
authors.forename: Nina
authors.initials: N
authors.lastname: Bilandžić
authors.forename: Ivana
authors.initials: I
authors.lastname: Kmetič
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D016466:CHO Cells; D053148:Caspase 3 / Q000096:biosynthesis; D002453:Cell Cycle / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D006224:Cricetinae; D003412:Cricetulus; D004247:DNA / Q000235:genetics; D052244:Endocrine Disruptors / Q000633:toxicity*; D004785:Environmental Pollutants / Q000633:toxicity*; D005260:Female; D009336:Necrosis; D010049:Ovarian Diseases / Q000139:chemically induced* / Q000473:pathology; D010053:Ovary / Q000473:pathology*; D011078:Polychlorinated Biphenyls / Q000633:toxicity*
chemical_list: D052244:Endocrine Disruptors; D004785:Environmental Pollutants; D004247:DNA; D011078:Polychlorinated Biphenyls; D053148:Caspase 3; C028451:3,4,3',4'-tetrachlorobiphenyl
keywords: Cell cycle progression; IC50 values; cell death; cytotoxicity; polychlorinated biphenyls