Short-term hypoxia and vasa recta function in kidney slices
Issue title: Selected papers of the 36th Conference of the German Society for Clinical Microcirculation and Hemorheology, 5–8. June, 2017, Greifswald, Germany
Guest editors: M. Jünger, A. Krüger-Genge and F. Jung
Affiliations: Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Germany
Correspondence:
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Corresponding author: Andreas Patzak, Institute of Vegetative Physiologie; Charité-Universitätsmedizin Berlin, Virchowweg 6, 10117 Berlin, Germany. Tel.: +49 30 450 528220/234; E-mail: [email protected].
Note: [1] Authors contribute equally to this work.
Abstract: BACKGROUND:Descending vasa recta (DVR) supply the inner part of outer renal medulla an area at risk for hypoxic damages. OBJECTIVE:We hypothesize increased vasoreactivity after hypoxia/re-oxygenation (H/R) in DVR, which might contribute to the reduced medullary perfusion after an ischemic event. METHODS:Live kidney slices (200μm) from SD rats were used for functional experiments. TUNEL assay and H&E staining were used to estimate slice viability. Kidney slices were treated with carbogen or hypoxia (1% O2) for 60 or 90 min and vasoreactivity to Ang II (10–7 M) was recorded by DIC microscopy after re-oxygenation with carbogen. Expression of NOS and NADPH enzymes mRNA were determined in iron-perfusion isolated VR. RESULTS:Percentage of apoptotic cells increased in control and H/R after 90 min in the medulla. Ang II– induced constriction of DVR was reduced after 90 min in control (compared to 60 min), but not after H/R. NOS enzymes mRNA expression levels decreased over 90 min hypoxia. CONCLUSIONS:Increased reactivity of DVR to Ang II after H/R compared to control (90 min) suggest a role of DVR in renal ischemia/reperfusion injury.
Keywords: Vasa recta, acute kidney injury, live kidney slices, hypoxia
