title: Na+/K+ -ATPase regulates tight junction formation and function during mouse preimplantation development.
abstract: Research applied to the early embryo is required to effectively treat human infertility and to understand the primary mechanisms controlling development to the blastocyst stage. The present study investigated whether the Na(+)/K(+)-ATPase regulates tight junction formation and function during blastocyst formation. To investigate this hypothesis, three experimental series were conducted. The first experiments defined the optimal dose and treatment time intervals for ouabain (a potent and specific inhibitor of the Na(+)/K(+)-ATPase) treatment. The results demonstrated that mouse embryos maintained a normal development to the blastocyst stage following a 6-h ouabain treatment. The second experiments investigated the effects of ouabain treatment on the distribution of ZO-1 and occludin (tight junction associated proteins). Ouabain treatment (up to 6 h) or culture in K(+)-free medium (up to 6 h) resulted in the appearance of a discontinuous ZO-1 protein distribution and a loss of occludin immunofluorescence. The third set of experiments examined the influence of ouabain treatment on tight junction function. Ouabain treatment or culture in K(+)-free medium affected tight junction permeability as indicated by an increase in the proportion of treated embryos accumulating both 4 kDa and 40 kDa fluorescein isothiocyanate (FITC)-dextran into their blastocyst cavities. The results indicate that the Na(+)/K(+)-ATPase is a potent regulator of tight junction formation and function during mouse preimplantation development.
authors.affiliation: Department of Physiology and Pharmacology, The University of Western Ontario, The Children's Health Research Institute-Victoria Research Laboratories, 800 Commissioners Road, London, Ontario, Canada N6A 4G5.
authors.forename: Michelle I
authors.initials: MI
authors.lastname: Violette
authors.forename: Pavneesh
authors.initials: P
authors.lastname: Madan
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Watson
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D002452:Cell Count; D004305:Dose-Response Relationship, Drug; D047108:Embryonic Development / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice / Q000378:metabolism*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D062793:Occludin; D010042:Ouabain / Q000378:metabolism / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D019108:Tight Junctions / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D062826:Zonula Occludens-1 Protein
chemical_list: D004791:Enzyme Inhibitors; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; C568986:Ocln protein, mouse; D010750:Phosphoproteins; C569042:TJP1 protein, human; C569043:Tjp1 protein, mouse; D062826:Zonula Occludens-1 Protein; D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase