Contractile apparatus of seminiferous tubule myoid cells

LOSINNO A.D; MORALES A; BERTOLDI M.V; AMAYA M.C; COSTANTINO V.V; LÓPEZ L.A

Puerto Madryn

Exposición; XLVI Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2010

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

Myoid cells (MC) surround the seminiferous tubules (ST) and express contractile proteins of muscle cells like -actin and myosin. Previous works postulated an orthogonal display of actin filaments (AF) forming a net. In this study we analyzed the distribution of AF and myosin II filaments (MF) of MC by confocal microscopy and TEM. Adult rat ST segments were isolated and maintained in control conditions or contracted with 50 nM ET-1. The segments were hatched with anti -actin-FITC or anti SMMII-IgG-Cy3 antibodies. Other segments were processed by conventional technique for TEM study. Confocal microscopy images of ST segments showed that MC contain both AF and MF distributed in two independent layers instead of a net: the inner layer with filaments perpendicular to the tubular axis and the external layer with filaments parallel. We confirmed this observation by TEM. In ST segments treated with ET-1, MC have smaller cellular area (1127±77,9 µm2 ± SEM) and bigger high (4,7±0,4 µm ± SEM) than controls (1823±68,8 µm2 and 3,3±0,2 µm respectively). TEM showed that MC of contracted segments have folded both nuclei and basement membranes, intertwined AF and MF, and a major anchorage of filaments to the plasma membrane. The knowledge of the participation of AF and MF in MC contraction is very important to understand the role that myoid cells carry out in the transport of sperm cells in the ST.