Transmission electron microscopy
Uterine tube fragments (approximately 1mm2) were fixed in Karnovsky’s solution (Sheehan and Hrapchak, 1980) for 4 h. The material was then washed with 0.1 M sodium cacodylate buffer (pH 7.2) and post-fixed in 1% osmium tetroxide for 2 h. The material was subsequently dehydrated in increasing concentrations of acetone and embedded in Epon resin. Ultrathin sections were obtained in an ultramicrotome and contrast stained with 2% uranyl acetate and 0.2% lead citrate. The material was examined and photographed using an EM 109-Zeiss transmission electron microscope in the Nucleus of Microscopy and Microanalysis at Federal University of Vic ̧ osa, Brazil.