SPATIAL ARRANGEMENT OF BETA ACTIN CYTOSKELETON IN THE SEMINIFEROUS EPHITELIUM: AN ULTRAMICROSCOPY TOMOGRAPHIC STUDY.

JUAN C. CAVICCHIA; CRISTIAN ACOSTA; MABEL FOSCOLO; JORGE IBAÑEZ; JUAN ROMERO; FRANCISCO CAPANI

CARTAGENA

Simposio; 12th INTER-AMERICAN MICROSCOPY CONGRESS; 2013

COMITÉ ORGANIZADOR CIASEM2013

  SPATIAL ARRANGEMENT OF BETA ACTIN CYTOSKELETON IN THE SEMINIFEROUS EPHITELIUM: AN ULTRAMICROSCOPY TOMOGRAPHIC STUDY. Juan Carlos Cavicchia, Cristian Acosta, Mabel Foscolo, Ibañez, Jorge,  Juan Romero, Francisco Capani Keywords: tubulobulbar complexes, beta actin,  seminiferous epithelium INTRODUCTION: The main goals of our study are the observation and the quantification of the spatial arrangement of beta actin filaments in Sertoli cells and germ cells in different stages of the spermatogenic cycle of the seminiferous tubules (1,2,3). To achieve these objectives, we used topographic techniques combined with high voltage transmission electron microscopy. MATERIAL AND METHODS: Adult Wistar rats were used. Vibratome-cut sections of 40 microns were included in Epon resin, incubated with an antibody against beta actin (Sigma, USA), then in the appropriate secondary antibody (Vector Laboratory Inc., Burlingame, CA ), developed with avidin/biotin peroxidase followed by 3,3?- diaminobenzidine and then observed with high voltage microscopes. This technique allows three-dimensional (3D) observation and reconstruction of thick sections (250 nm). Our results are presented as a sequence of tomograms. These high resolution video images provide unique and original observations of the frequency of occurrence of tubulobulbar complexes located between elongated spermatids near spermiation and the sustentacular Sertoli cell. We  also observe multi-vesicular bodies, which Sertoli cells use to recycle beta actin (1). Notice that beta actin is the main cytoskeletal component of the intercellular junctions and tubulo-bulbar complexes in the seminiferous  epithelium, hence its histological and functional importance. CONCLUSSIONS: To our knowledge this is the first direct observation of the tubule-bulbar processes in a 3D high resolution projection. These observations are original because they needed to be captured using thick sections (0.25 micron) combined with unique intermediate voltage electron microscopes with 3D reconstruction.