Trehalose delivered by cold-responsive nanoparticles improves tolerance of cumulus-oocyte complexes to microwave drying

PurposeTrehalose is a non-permeable protectant that is the key to preserve live cells in a dry state for potential storage at ambient temperatures. After intracellular trehalose delivery via cold-responsive nanoparticles (CRNPs), the objective was to characterize the tolerance of cat cumulus-oocyte complexes (COCs) to different levels of microwave-assisted dehydration.MethodsTrehalose was first encapsulated in CRNPs. After exposure to trehalose-laden CRNPs, different water amounts were removed from cat COCs by microwave drying. After each dehydration level, meiotic and developmental competences were evaluated via in vitro maturation, fertilization, and embryo culture. In addition, expressions of critical genes were assessed by quantitative RT-PCR.ResultsCRNPs effectively transported trehalose into COCs within 4 h of co-incubation at 38.5 degrees C followed by a cold-triggered release at 4 degrees C for 15 min. Intracellular presence of trehalose enabled the maintenance of developmental competence (formation of blastocysts) as well as normal gene expression levels of HSP70 and DNMT1 at dehydration levels reaching up to 63% of water loss.ConclusionIntracellular trehalose delivery through CRNPs improves dehydration tolerance of COCs, which opens new options for oocyte storage and fertility preservation at ambient temperatures.

Automated summary

Intracellular trehalose delivery through CRNPs improves the dehydration tolerance of COCs, opening up new possibilities for oocyte storage and preservation of fertility at ambient temperatures.