Controlled Stress Improves Oocyte Performance – Cell Preconditioning in Assisted Reproduction

A recently emerged concept utilizing a controlled environmen-tal impact as a treatment for cells and tissues aims to improveneither the in vitro conditions nor the procedures, but the cellitself. Hydrostatic pressure stress emerged as the mostcontrollable and most effective stressor, proving the principlethat controlled stress improves cell performance in in vitroprocedures, whereas further studies using different stressors(osmotic, oxidative or mechanic stresses) supported the prin-ciple. The present summary reviews studies of various stresstreatments to treat oocytes of three species (murine, porcine,human) before vitrification, in vitro maturation, enucleationand somatic cell nuclear transfer. Eventually, cleavage andblastocyst rates and – in cases when hydrostatic pressure wasused – blastocyst cell number and birth rates as well weresignificantly improved compared to untreated controls.