TITLE:
Estimating zona pellucida hardness under microinjection to assess oocyte/embryo quality: Analytical and experimental studies
AUTHORS:
Morteza Khalilian, Mojtaba Rezazadeh Valojerdi, Mehdi Navidbakhsh, Mahmoud Chizari, Poopak Eftekhari-Yazdi
KEYWORDS:
Human Oocyte; Human Embryo; Intracytoplasmic Sperm Injection; Zona Pellucida Hardness
JOURNAL NAME:
Advances in Bioscience and Biotechnology,
Vol.4 No.5,
May
30,
2013
ABSTRACT: The precise determination of zona pellucida (ZP)
hardness is largely unknown due to the lack of appropriate measuring and
modelling methods. In this study, we have used experimental and theoretical
models to describe the mechanical behavior of a single oocyte cell to improve
the assisted reproductive technology (ART) outcomes by assessing oocyte/embryo
quality. This paper presents the development of: i) a microinjection model to
estimate the force of ZP penetration, ii) a micropipette aspiration model to
determine the corresponding hardness, and iii) an experimental procedure to
generate the required data for these two models. Our results show that the estimated penetration force provides a performance target for the penetration
process during intracytoplasmic sperm injection (ICSI), while the estimated
corresponding hardness serves as an indicator of the extent of deformation
sustained by the oocyte prior to penetration. Evaluation of these results shows
that a routine assessment of ZP hardness under microinjection would allow for
the identification of certain oocyte pools for which further manipulation is
recommended in order to improve injection, hatching and finally ART outcomes.