Stress for Stress Tolerance? A Fundamentally New Approach in Mammalian Embryology1

Abstract

In vitro culture, storage, and manipulation of gametes and embryos require meticulously adjusted conditions to avoid or minimize the harmful effects of uncontrolled stress. However, recent work indicates that a well-defined and properly applied stress may induce general adaptation and increase tolerance to various in vitro procedures. The aim of this review is to summarize reports on the effects of stress on gametes and embryos of several species. Treatment with sublethal doses of high hydrostatic pressure (HHP), or osmotic, heat, or oxidative stress resulted in increased morphological survival, fertilizing ability, or developmental potential after various in vitro or in vivo procedures. HHP treatment of spermatozoa, oocytes, embryos, and embryonic stem cells increased fertilizing ability, developmental competence, and differentiation and improved results after cryopreservation, parthenogenetic activation, intracytoplasmic sperm injection, and somatic cell nuclear transfer. Osmotic stress of oocytes resulted in higher developmental rates after cryopreservation, parthenogenetic activation, and somatic cell nuclear transfer. Heat shock was reported to increase developmental competence of parthenogenetically activated oocytes. Although cellular and subcellular mechanisms supposedly contributing to these processes require further research, the new principle, i.e., to improve the stress tolerance by a defined sublethal stress, may outline a completely new strategy in mammalian embryology, as well as cryopreservation of other cells and tissues with remarkable theoretical and practical consequences.

Sperm surface changes and physiological consequences induced by sperm handling and storage

“…The preferred method is high hydrostatic pressure (HHP), as it can be applied with the aid of a programmable device in an instantaneous, uniform and consistent manner (Pribenszky et al 2010). Optimisation of pressure, temperature and exposure time has produced improvements in the quality and fertility of fresh, chilled and frozen-thawed bull and boar spermatozoa (reviewed by Callesen (2010), Pribenszky et al (2010) and Pribenszky & Vajta (2011)). However, the mechanism by which HHP treatment confers increased resistance to stress is not known.…”

Factors Affecting Cryopreservation of Porcine Oocytes

“…The basic principal of their method is to treat gametes or embryos with sublethal stresses such as with high hydrostatic pressure or osmotic, heat, or oxidative stress which increased survival rates during cryopreservation and subsequent developmental competence in various cell types presumably by inducing the production of stress-proteins in them [78]. This approach has been reported to improve development of vitrified porcine M-II stage oocytes to the blastocyst stage after parthenogenetic activation from 0% to 13.1% by the use of high hydrostatic pressure [37] and from 3 to 9% by the use of osmotic stress [39].…”

The use of immature oocytes in the fertility preservation of cancer patients: current promises and challenges

“…More recently, innovative approaches that take advantage of controlled sublethal physiological stresses have been explored in animal models. The rationale behind a 'stress for stress tolerance' approach lies in the induced ability of the exposed oocytes to resist stresses associated with cryopreservation, through perhaps increased synthesis or activation of endogenous proteins/mechanisms that afford protection to the oocyte (reviewed by Pribenszky et al, 2010).…”