Use of melatonin as an inhibitor of apoptotic process for cryopreservation of zebrafish (Danio rerio) embryos

Abstract This study investigated the use of melatonin to arrest effects apoptosis in vitrified zebrafish (D. rerio) embryos. Dechorionated embryos at 22-24 somite-stage were divided (n = 60/treatment) into a non-vitrified (Control Group, 0 M melatonin) and treatments with (T1), 1 µM (T2) mM (T3). For treatments, solution methanol/propylene glycol based was used stored -196 °C for week. After thaw, survival rate, scanning electron microscopy, expression anti (bcl-2) pro-apoptotic (bax/caspase-3) genes, reactive oxygen species (ROS) formation DNA fragmentation analyses performed. No live obtained from observing rapid degeneration immediately after thawing, vitelline layer rupture leakage its content, followed by breakdown epithelial cells melanisation tissue. Regarding apoptotic process, T3 had highest relative gene expression, three genes (P < 0.05) furthermore, T2 similar CG 0.05). ROS revealed that presented lower percentage embryo surface area affected (3.80 ± 0.40%) 0.05), contrast, no differences found among other groups. T1 most significantly damaged fragmentation. The groups damage levels > inclusion vitrifying solution, countered process post-thaw embryos, suggesting utility cryopreserving fish