In Vitro Interactions of Eutherian Ova/Spermatozoa: Significance for Orientation/Binding of Gametes

Abstract

Ova are observed in vitro to rotate counterclockwise immediately following sperm attachment. This phenomenon was examined in both human-hamster and hamster-hamster systems. The counterclockwise rotation has been found to be directly proportional to the efficiency of in vitro penetration or fertilization. These observations indicate that the eutherian ova possess a definite polarity and that the sperm attachment follow a given geometry.

The Fertilization Dance: A Mechanical View of the Egg Rotation During the Initial Spermatozoa–Ovum Interaction

“…Thus, using these estimates in eqn (37), we obtain +50/N. It is clear that a minimal amount of spermatozoa attempting penetration, that is naturally 178 A. NIR accumulated at a very early stage after insemination, will render the value of (1 and that a rotation of the cluster can be expected soon after the encounter began, in agreement with the reported observations (Nilsson et al, 1986;Kamiguchi and Mikamo, 1986;Rosenbush et al, 1989;Chaudhuri et al, 1991). Furthermore, since the model predicts that the intensity of rotation is proportional to (1!…”

“…Rather, we are concerned here with the slow rotation of the entire cluster of ovum and the spermatozoa that adhere to its external periphery just before penetration. This rotation was observed and documented in vivo (Nilsson et al, 1986) and was reported in various in vitro experiments (Kamiguchi & Mikamo, 1986;Rosenbush et al, 1989;Chaudhuri et al, 1991). The various studies report that the rotation phenomenon exists for eggs with intact cumulus or eggs with exposed zona pellucida as well as for zona free ova.…”

“…In vitro experiments suggest that this case is the more common observation (Chaudhuri et al, 1991). Without loss of qualitative generality, we shall henceforth assume that the preferred rotation axis is normal to the adjacent wall.…”

“…Some in vitro homologous fertilization studies suggest that a higher penetration rate and a higher order of polyspermy were observed when the ova rotated faster (Chaudhuri et al, 1991). This increase could be attributed to a higher number of attached sperms.…”

“…Several studies report that, immediately following sperm attachment, the egg begins rotating slowly (Yanagimachi, 1981;Kamiguchi & Mikamo, 1986;Rosenbush et al, 1989;Chaudhuri et al, 1991). We do not refer here to rotations that are observed in various species following fertilization, and which occur following the penetration of the sperm and before the "rst cleavage (see, e.g.…”