Morphological and Molecular Alterations Induced by Lead in Embryos and Larvae of Danio rerio

Abstract

Lead (Pb) is one of the most toxic and persistent elements and may adversely affect both humans and wildlife. Given the risks posed to humans, lead is listed among priority substances of public health importance worldwide. In fish, available studies deal with high doses, and the potential hazard of Pb at low concentrations is largely unknown. Given its well-demonstrated translational value for human toxicity research, we used zebrafish as a model species. Embryos were exposed to two environmentally relevant concentrations of lead (2.5 and 5 µg/L) from 6 h post-fertilization and analyzed after 48, 96, and 144 h. The morphological abnormality arose after 48 h, and the incidence and intensity were dose and time dependent. Spinal and tail deformities were the most frequently detected alterations. Pb also modulated the expression of genes involved in the toxicological responses (sod and mt), thus demonstrating that zebrafish’s early stages are able to mount an adaptive response. Moreover, ldh and β-catenin were significantly upregulated in all groups, whereas wnt3 expression was increased in the high concentration group. Our results confirm that zebrafish embryos and larvae are valuable early warning indicators of pollution and may play a major role in ecosystems and human health monitoring.

Morphological and Functional Alterations Induced by Two Ecologically Relevant Concentrations of Lead on Danio rerio Gills

“…The molecular analysis clearly showed significant induction of MTs following Pb administration in Danio rerio gills in all experimental groups, according to previous reports on both freshwaters [ 67 , 68 ] and marine species [ 29 ]. Moreover, this result agrees with our previous study showing an MTs induction after lead exposure in embryo and larvae of the same species, thus demonstrating that zebrafish has a precocious ability to mount an adaptive response and maintain it into adulthood [ 8 ]. Interestingly, the upregulation observed here was more pronounced as early as 48 h of exposure in both low and high concentration groups and then decreased, still remaining higher than the control group.…”

“…Lead (Pb) represents 0.002% of the Earth’s crust and is ranked as the second most harmful environmental element [ 8 , 9 ]. Due to its abundance, rapid and high bioaccumulation, and long biological half-life, it gained more attention among other heavy metals (i.e., cadmium, chromium, and nickel) and is of great concern in food safety debates (FSS) worldwide [ 10 ].…”

Exploring Periostracum as an Alternative Root Canal Irrigant: Insights From Zebrafish Embryo Experiments

“…In each treatment group, the number of hatched larvae was recorded, and the hatching rate (%) was calculated using the formula: hatched numbers/total exposed numbers × 100. The number of hatched embryos is then tallied and compared to the total used to calculate the hatching rate [22].…”

Comparative Analysis of the Cytotoxic Effects of Modified Triple Antibiotic Hydrogel: Insights From Experimental Models

“…The number of hatched embryos is then counted and compared to the total number of embryos used in the experiment to calculate the hatching rate. The count of hatched larvae was recorded for each treatment group, and the hatching rate (%) was calculated using the formula: (number of hatched larvae / total number of exposed larvae) × 100 [18].…”