IHEM   20887
INSTITUTO DE HISTOLOGIA Y EMBRIOLOGIA DE MENDOZA DR. MARIO H. BURGOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Changes in Myoid Cells Actin Network by Contraction.
Autor/es:
L.A. LOPEZ, MV. BERTOLDI, JC CAVICCHIA, A MORALES E. CALLEGARI.
Lugar:
San Francisco, CA. USA
Reunión:
Congreso; 48 th Annual Meeting The American Society for Cell Biology.; 2008
Institución organizadora:
The American Society for Cell Biology
Resumen:
In the mammalian testis, peritubular myoid cells (PMCs) surround seminiferous tubules (STs).  These cells are contractile and express the cytoskeletal markers of true smooth muscle, such as alpha-isoactin and F-actin, and participate in the contraction of seminiferous tubules during the transport of spermatozoa and testicular fluid to the rete testis. The goal of this work was to analyze the changes in the PMC actin network induced by contraction. ST contraction was assayed by incubating isolated STs with or without 50 nM endothelin-1 or 100 nM oxytocin  in MEM for 20 sec at 22 °C, followed by immediate fixation with 4 % paraformaldehyde  in PBS. STs were incubated with anti-alfa actin-FITC conjugated antibody. The samples was mounted with mowiol and analyzed in a confocal inverted microscope. For actin filaments analysis 10 sequential fluorescent images of the same field were acquired in successive 1 µm z axis displacements as we scanned through the PMC layer in the wall of ST with a Plan Apo N60 X objetive. The z series of fluorescence section were analyzed  with  a Image J program to obtain a Z-stack image of maximal intensity proyection. The Z-stack image of PMCs from unstimulated STs (control) showed the characteristic orthogonal meshwork of actin filaments. While in STs stimulated with endothelin-1, the actin filament network evinced undulating actin filaments, losing the orthogonal organization characteristic of control PMCs. This pattern of actin filament organization was observed in the whole ST wall, but differed from previous descriptions where endothelin-1 induced an actin filament network reduced in size, and organized in bundles in a centrally located regions of the cell. To the best of our knowledge, this is the first time that a Z-stack image of the actin network from PMCs is described, and shows different details of actin organization compared to conventional light microscopy. Meanwhile, PMCs from oxytocin stimulated STs showed the typical orthogonal network of actin filament found in PMCs of control STs.