Cultivation of oviduct epithelial cells on porous filters fosters in vivo-like morphology and functionality. However, due to the optical properties of the filter materials and the cells’ columnar shape, cell quality is hard to assess via light microscopy. In this study, we aim to evaluate transepithelial electrical resistance (TEER) measurement as a prognostic quality indicator for the cultivation of porcine oviduct epithelial cells (POEC). POEC were maintained in four different types of media for 3 and 6 w to achieve diverse culture qualities, and TEER was measured before processing samples for histology. Culture quality was scored using morphological criteria (presence of cilia, confluence and cell polarity). We furthermore analyzed the correlation between cellular height (as a measure of apical–basal polarization) and TEER in fully differentiated routine cultures (biological variation) and in cultures with altered cellular height due to hormonal stimulation. Fully differentiated cultures possessed a moderate TEER between 500 and 1100 Ω*cm2. Only 5 % of cultures which exhibited TEER values in this defined range had poor quality. Sub-differentiated cultures showed either very low or excessively high TEER. We unveiled a highly significant (P < 0.0001) negative linear correlation between TEER and epithelial height in well-differentiated cultures (both routine and hormone stimulated group). This may point toward the interaction between tight junction assembly and epithelial apical–basal polarization. In conclusion, TEER is a straightforward quality indicator which could be routinely used to monitor the differentiation status of oviduct epithelial cells in vitro.Electronic supplementary materialThe online version of this article (doi:10.1007/s00418-015-1351-1) contains supplementary material, which is available to authorized users.

Peritendinous tissue fibrosis which leads to poor tendon function is a worldwide clinical problem; however, its mechanism remains unclear. Transcription factor RelA/p65, an important subunit in the NF-κB complex, is known to have a critical role in many fibrotic diseases. Here, we show that RelA/p65 functions as a core fibrogenic regulator in tendon adhesion and that its inhibition exerts an anti-fibrogenic effect on peritendinous adhesion. We detected the upregulation of the NF-κB pathway in human tendon adhesion using a gene chip microarray assay and revealed the overexpression of p65 and extracellular matrix (ECM) proteins Collagen I, Collagen III, and α-smooth muscle actin (α-SMA) in human fibrotic tissues by immunohistochemistry and western blotting. We also found that in a rat model of tendon injury, p65 expression correlated with tendon adhesion, whereas its inhibition by small interfering (si)RNA prevented fibrous tissue formation and inflammatory reaction as evidenced by macroscopic, biomechanical, histological, immunohistochemical, and western blotting analyses. Furthermore, in cultured fibroblasts, p65-siRNA, p65-specific inhibitor, Helenalin and JSH23 suppressed cell proliferation and promoted apoptosis, whereas inhibiting the mRNA and protein expression of ECM components and cyclo-oxygenase-2, an inflammatory factor involved in tendon adhesion. Our findings indicate that p65 has a critical role in peritendinous tissue fibrosis and suggest that p65 knockdown may be a promising therapeutic approach to prevent tendon adhesion.

We developed an air-liquid interphase culture procedure for mammalian oviduct epithelial cells leading to the formation of functional epithelial tissues, which generate oviduct fluid surrogates. These in vitro oviduct epithelia can be co-cultured with living zygotes and enable embryonic development up to the blastocyst stage without addition of embryo culture medium. The described strategy is broadly applicable to analyze early embryo-maternal interactions under standardized in vitro conditions.