Lead Exposure Causes Spinal Curvature during Embryonic Development in Zebrafish

Lead (Pb) is an important raw material for modern industrial production, they enter the aquatic environment in several ways and cause serious harm to aquatic ecosystems. Lead ions (Pb²⁺) are highly toxic and can accumulate continuously in organisms. In addition to causing biological deaths, it can also cause neurological damage in vertebrates. Our experiment found that Pb²⁺ caused decreased survival, delayed hatching, decreased frequency of voluntary movements at 24 hpf, increased heart rate at 48 hpf and increased malformation rate in zebrafish embryos. Among them, the morphology of spinal malformations varied, with 0.4 mg/L Pb²⁺ causing a dorsal bending of the spine of 72 hpf zebrafish and a ventral bending in 120 hpf zebrafish. It was detected that spinal malformations were mainly caused by Pb²⁺-induced endoplasmic reticulum stress and apoptosis. The genetic changes in somatic segment development which disrupted developmental polarity as well as osteogenesis, resulting in uneven myotomal development. In contrast, calcium ions can rescue the series of responses induced by lead exposure and reduce the occurrence of spinal curvature. This article proposes new findings of lead pollution toxicity in zebrafish.