Understanding osmoregulation, cryoprotectant toxicity, and cold tolerance in sea urchin eggs: Implications for cryopreservation.

This study investigates the challenges and potential solutions for cryopreserving sea urchin (Paracentrotus lividus) eggs. It focuses on understanding the thresholds and osmoregulatory mechanisms, cryoprotectant toxicity, and cold tolerance in these eggs, which are especially difficult to preserve due to high sensitivity to cryoprotectants and low-temperature injury. Key findings suggest that stepwise addition of cryoprotectants, particularly dimethyl sulfoxide (Me2SO) combined with other agents like DMF or methanol, reduces toxicity and enhances larval survival. The study also highlights that short-term exposure to low temperatures (4 °C) minimally impacts egg viability, offering insights for optimizing cooling protocols. By examining osmolarity, salinity, and cryoprotectant interactions, the research proposes vitrification as a promising cryopreservation technique. These findings will contribute to refining current embryo cryopreservation protocols and provides information for the future vitrification of sea urchin eggs, with implications for marine conservation and aquaculture.