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    Sheep rumen and omasum primary cultures and source epithelia: barrier function aligns with expression of tight junction proteins (2011)

    Art
    Zeitschriftenartikel / wissenschaftlicher Beitrag
    Autoren
    Stumpff, F.
    Georgi, M. I.
    Mundhenk, L.
    Rabbani, I.
    Fromm, M.
    Martens, H.
    Günzel, D.
    Quelle
    Journal of Experimental Biology; 214(Pt 17) — S. 2871–2882
    ISSN: 0022-0949
    Sprache
    Englisch
    Verweise
    Pubmed: 21832130
    Kontakt
    Institut für Veterinär-Physiologie

    Oertzenweg 19 b
    14163 Berlin
    Tel.+49 30 838 62600 Fax.+49 30 838-62610
    email:physiologie@vetmed.fu-berlin.de

    Abstract / Zusammenfassung

    The forestomachs of cows and sheep have historically served as important models for the study of epithelial transport. Thus, the ruminal epithelium was among the first tissues in which absorption of chloride against an electrochemical gradient was observed, requiring a tight paracellular barrier to prevent back-leakage. However, little is known about ruminal barrier function, despite the considerable implications for ruminant health. The tight junction proteins of the omasum have never been investigated, and no cell culture model exists. We present a new method for the isolation of cells from forestomach epithelia. Protein expression of cells and source tissues of sheep were studied using western blot, PCR and confocal laser scanning microscopy. Cultured cells were characterized by transepithelial resistance (TER) measurements and patch clamping. Cells developed TER values of 729±134 Ω cm(2) (rumen) and 1522±126 Ω cm(2) (omasum). Both primary cells and source epithelia of rumen and omasum expressed cytokeratin, occludin and claudins 1, 4 and 7 (but not claudins 2, 3, 5, 8 and 10), consistent with the observed paracellular sealing properties. Staining for claudin-1 reached the stratum basale. The full mRNA coding sequence of claudins 1, 4 and 7 (sheep) was obtained. Patch-clamp analyses of isolated cells proved expression of an anion conductance with a permeability sequence of gluconate<acetate<chloride. This is in accordance with a model that ruminal and omasal transport of anions such as chloride and acetate has to occur via a transcellular route and involves channel-mediated basolateral efflux, driven by Na(+)/K(+)-ATPase.