Heterocellular communication in the heart: electron tomography of telocyte-myocyte junctions.

This study was performed on mouse heart samples obtained from 8-month-old C57BL/6 mice. The tissue samples were processed according to routine Epon-embedding procedure, as previously described [ 5 , 7 ]. The thin and thick sections were cut with a diamond knife using an RMC ultramicrotome (Boeckeler Instruments, Inc., Tucson, AZ, USA) and double stained with 1% uranyl acetate and Reynolds lead citrate. 1. Transmission electron microscopy was performed on 60-nm-thin sections using a Morgagni 286 transmission electron microscope (FEI Company, Eindhoven, The Netherlands) at 60 kV. Digital electron micrographs were recorded with a MegaView III charged-coupled device (CCD) using iTEM-SIS software (Olympus, Soft Imaging System GmbH, Münster, Germany). 2. ET was performed was performed on 250-nm-thick sections using a Tecnai G2 Spirit BioTwin electron microscope with single-tilt specimen holder (FEI Company) at 100 kV and electron tomographic data sets were recorded with a MegaView G2 CCD camera (Olympus) in ET mode [ 31 , 32 ]. Tomographs were acquired at 1° angular increment from –65° to +65° about an axis perpendicular to the optical axis of the microscope, at 36,000× magnifications (1.64 nm/px). After data alignment, the data sets were reconstructed into 3D volume (data collection, reconstruction and visualization) using Xplore3D Tomography Suite software (FEI Company). Amira 5.0.1 software (Visage Imaging GmbH, Berlin, Germany) was used for 3D imaging.