Molecular aspect of silver nanoparticles regulated embryonic development in Zebrafish (Danio rerio) by Oct-4 expression

Abstract

With the enhancement of commercial manifestation of silver nanoparticles, concerned has risen on their accumulation in aquatic system and consequent effects on fish development and metabolism. In this study, experiments were conducted to assess the impacts of silver nanoparticles on early life cycles of fish considering Zebrafish (Danio rerio) as experimental model. Silver nanoparticles were synthesized through chemical reduction method and characterized through UV-visible spectroscopy, dynamic light scattering (DLS), and HR-TEM. Different sub lethal doses of nanosilver were applied (13.6, 21.6, 42.4, 64, and 128 μgL^-1) to post-fertilization phases of Zebrafish embryos and their interaction effects were monitored up to six days period. No significant morphological variations were observed at 13.6, 21.6, 42.4 μgL^-1 dose of silver nanoparticles, whereas 64 and 128 μgL^-1 exposure dose exhibited bending in myotome, deformity in tail region, somites, notochord and swelling in anterior and posterior region of embryos and larva. Hatching performances analysis elicited highest hatching success in 13.6 and 21.6 μgL^-1 doses of silver nanoparticles followed by positive and negative control, whereas exposure dose of 64 and 128 μgL^-1 exhibited comparatively lower success. Western blot analysis were conducted on developing hatchlings with Oct4 antibody and at 13.6 and 21.6 μgL^-1dose,it showed over expression elucidating stimulatory role of nanosilver in these mentioned doses. In silico analysis depicted a firm interaction of nanosilver with Oct4 revealing their key role in growth stimulation of developing embryos. The study demonstrates the function of nanosilver as a growth promoter rather only as a toxicant in fish metabolic system.

Keywords: Bioinformatics tools; Breeding; Danio rerio; Development; Oct-4; Silver nanoparticles.