Mechanical properties of zona pellucida hardening

Papi, Massimiliano; Brunelli, Roberto; Sylla, Lakamy; Parasassi, Tiziana; Monaci, Maurizio; Maulucci, Giuseppe; Missori, Mauro; Arcòvito, Giuseppe; Ursini, Fulvio; Spirito, Marco De

doi:10.1007/s00249-009-0468-3

Cited by 66 publications

(63 citation statements)

References 22 publications

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“…Its viscoelastic properties are modified according to the time elapsing from ovulation. This has been reported for cow eggs [46], although these authors assumed an increased resistance of the zona pellucida to proteolytic digestion as a consequence of fertilisation. However, this does not happen in cow eggs.…”

Section: Oviduct Fluidsmentioning

confidence: 76%

Considerations of viscosity in the preliminaries to mammalian fertilisation

Hunter¹,

Coy

Gadea

et al. 2011

J Assist Reprod Genet

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Migration of spermatozoa in the female genital tract will be strongly influenced by the viscosity of the fluids encountered, yet little systematic analysis has been given to such a consideration. This essay reviews the series of milieux confronting a fertilising sperm during its progression to the oviduct ampulla. Two groups are discussed, first those in which ejaculation is into the vagina, second those in which semen enters the uterus during a protracted mating. Viscous glycoprotein secretions that accumulate in the oviduct isthmus of both groups before ovulation are highlighted, as is the environment generated in the ampulla by the post-ovulatory suspension of oocyte(s), cumulus cells and spermatozoa; follicular and peritoneal fluids may also be present. The viscosity of all female tract fluids responds to cyclical variations in temperature, and these exist within the oviduct near the time of ovulation. Gradations in viscosity influence the pattern and strength of sperm flagellar activity and the rate of forward movement. Measurements of sperm motility are currently made in a physiological medium of constant viscosity and temperature, thereby overlooking changes in the female genital tract. A more sophisticated approach might reveal an adequate fertilising potential in a proportion of putatively poor semen samples.

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Section: Oviduct Fluidsmentioning

confidence: 76%

Considerations of viscosity in the preliminaries to mammalian fertilisation

Hunter¹,

Coy

Gadea

et al. 2011

J Assist Reprod Genet

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“…AFM was used to evaluate mechanical properties of immature, mature and fertilized bovine oocyte ZPs [13,14], also trying to assess the effect of ZP structure inhomogeneity across membrane thickness [15,16], and the role played by residual stresses that develop in the tested ZP membrane (which is originally spherical shaped) when specimens are spread out on a rigid substrate for nanoindentation measurements [17].…”

Section: Introductionmentioning

confidence: 99%

A hybrid characterization framework to determine the visco-hyperelastic properties of a porcine zona pellucida

et al. 2014

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The zona pellucida (ZP) is a specialized extracellular matrix surrounding the developing oocyte. This thick matrix consists of various types of glycoprotein that play different roles in the fertilization process. Nowadays, several techniques are available for assessing ZP's mechanical response. The basic assumption behind these methods is that the ZP behaves like an elastic body: hence, dissipative forces are neglected and Young's modulus remains unaffected by probe dynamics. However, dissipative forces are strongly regulated by the slippage of ZP chains past one another while reaction forces related to elastic deformations (driven by the ability of each chain to stretch) depend on the ZP structure (i.e. number of cross-links and distances between knots). Although viscous reaction forces generated by the ZP are one of the main factors regulating sperm transit, their peculiar behaviour along the ZP structure remains poorly understood and rarely investigated. In order to overcome this limitation, a novel visco-hyperelastic model describing the porcine ZP reaction forces generated by nanoindentations at different probe rates is developed and verified in this study. Visco-hyperelastic parameters of porcine ZP membranes are determined by means of a hybrid characterization framework combining atomic force microscopy nanoindentation measurements, nonlinear finite-element analysis and nonlinear optimization. Remarkably, it is possible to separate the contributions of hyperelastic and viscous terms to ZP mechanical response and evaluate the error made in the determination of ZP mechanical properties if viscous effects were not considered.

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“…After the secretion of the cortical content into the perivitelline space, this will lead to modifications of the zona pellucida structure [20][21][22][23]. In some species, this has been characterized as "zona hardening" defined as resistence to proteolytic digestion resulting in a zona pellucida that cannot be penetrated by acrosome-reacted sperm, and also cannot be recognized by acrosome-intact sperm [24][25][26]. Therefore, successful fertilization of an oocyte depends on three independent and quite differently organized membrane fusion events.…”

Section: Introductionmentioning

confidence: 99%

Membrane Fusions During Mammalian Fertilization

Gadella

Evans

2011

Advances in Experimental Medicine and Biology

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Successful completion of fertilization in mammals requires three different types of membrane fusion events. Firstly, the sperm cell will need to secrete its acrosome contents (acrosome exocytosis; also known as the acrosome reaction); this allows the sperm to penetrate the extracellular matrix of the oocyte (zona pellucida) and to reach the oocyte plasma membrane, the site of fertilization. Next the sperm cell will bind and fuse with the oocyte plasma membrane (also known as the oolemma), which is a different type of fusion in which two different cells fuse together. Finally, the fertilized oocyte needs to prevent polyspermic fertilization, or fertilization by more than one sperm. To this end, the oocyte secretes the contents of cortical granules by exocytotic fusions of these vesicles with the oocyte plasma membrane over the entire oocyte cell surface (also known as the cortical reaction or cortical granule exocytosis). The secreted cortical contents modify the zona pellucida, converting it to a state that is unreceptive to sperm, constituting a block to polyspermy. In addition, there is a block at the level of the oolemma (also known as the membrane block to polyspermy). IntroductionFertilization of the oocyte involves three membrane fusion events [1] namely, (1) a preparative series of secretion membrane fusions at the apical sperm surface known as acrosome exocytosis [2]. The membrane fusions are induced when the sperm cell binds to specific zona binding proteins at the sperm surface [3][4][5][6][7]. The acrosome exocytosis is a multipoint membrane fusion event between the sperm plasma membrane and the outer acrosomal membrane (see Fig. 5.1 [8,9]) and the exposed acrosomal content is required for sperm to penetrate the zona pellucida [10][11][12]. This so-called zona drilling effectively takes place because the sperm at this stage also has acquired hyperactivated motility [13]. (2) After zona penetration the sperm enters the perivitelline space where it can bind and fuse with the oocyte plasma membrane [14,15]. This is the actual fertilization fusion in which the contents of the sperm are delivered into the oocyte cytoplasm. The plasma membrane of the equatorial segment (see Fig. 5.1) is the site where proteins are located that orchestrate sperm-oocyte binding and fusion [16]. (3) In order to prevent polyspermy the oocyte has to activate defense systems to block redundant sperm-oocyte fusion [17]. To this end the first fertilizing sperm delivers activation factors

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Mechanical properties of zona pellucida hardening

Cited by 66 publications

References 22 publications

Considerations of viscosity in the preliminaries to mammalian fertilisation

Considerations of viscosity in the preliminaries to mammalian fertilisation

A hybrid characterization framework to determine the visco-hyperelastic properties of a porcine zona pellucida

Membrane Fusions During Mammalian Fertilization

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