Extensor Digitorum Longus Muscle Analysis in LAT1 mKO Mice

LAT1 mKO mice were provided as a gift by Dr. Peter Taylor of the University of Dundee. Methods of generation of this mouse strain have been previously described [14 (link)]. Mice (n = 2 mKO, n = 2 wild type (WT)) were housed in a climate-controlled facility at the University of California Davis, in a standard 12 h light/dark cycle and fed standard chow ad libitum. All procedures were approved by the UC Davis Institutional Animal Care and Use Committee (IACUC) and performed under protocol number 19244. At three months of age, mice were fasted for 5 h before the extensor digitorum longus (EDL) muscle was surgically removed under anaesthetic (2.5% isofluorane), pinned to cork and frozen in liquid nitrogen-cooled isopentane. Muscles were subsequently stored at −80 °C until sectioned. Prior to sectioning, the belly of the EDL was blocked in Tissue-Tek Optimal Cutting Temperature (OCT) Compound (VWR International, Leicestershire, UK) and frozen in liquid nitrogen-cooled isopentane, at which point the sample was ready for cryo-sectioning. During staining protocols, both WT and mKO samples were processed and stained simultaneously, and image capture paradigms were also identical.