Biophysical properties of the zona pellucida measured by capillary suction: is zona hardening a mechanical phenomenon?

Published

Journal Article

Following fertilization, the zona pellucida, a glycoprotein shell investing mammalian eggs, becomes more resistant to dissolution by various agents. This decreased solubility, termed zona hardening, does not occur in hamsters. Thus, universal roles of zona hardening in the block to polyspermy and in oviductal interaction with embryos have been discounted. Although these roles probably have mechanical components, zona hardening has been assessed only as decreased solubility. In our studies, mouse and hamster ovulated oocytes were compared with 2-cell embryos by capillary suction. Step changes in pipet pressure were measured manometrically while resulting zona deformations were determined videomicrographically. Both mouse and hamster zonae were more "deformable" in oocytes than embryos. These results suggest that mechanical zona hardening may be a universal phenomenon. In addition to zona hardening following fertilization, a "spontaneous" zona hardening phenomenon has been reported for mouse oocytes (not embryos) cultured in vitro. In our system, this spontaneous decrease in zona solubility by protease was not accompanied by a mechanical change. In contrast, hamster oocyte and embryo zonae became slightly more soluble, and considerably more deformable during 4-h culture. Thus, spontaneous zona hardening is not a universal phenomenon, and, while decreased solubility has been called "hardening", it is not always accompanied by a mechanical change.

Full Text

Duke Authors

Cited Authors

  • Drobnis, EZ; Andrew, JB; Katz, DF

Published Date

  • February 1, 1988

Published In

Volume / Issue

  • 245 / 2

Start / End Page

  • 206 - 219

PubMed ID

  • 3367125

Pubmed Central ID

  • 3367125

Electronic International Standard Serial Number (EISSN)

  • 1097-010X

International Standard Serial Number (ISSN)

  • 0022-104X

Digital Object Identifier (DOI)

  • 10.1002/jez.1402450210

Language

  • eng