Anti-Osteogenic Activity of Cadmium in Zebrafish

Abstract

Among the many anthropogenic chemicals that end up in the aquatic ecosystem, heavy metals, in particular cadmium, are hazardous compounds that have been shown to affect developmental, reproductive, hepatic, hematological, and immunological functions in teleost fish. There is also evidence that cadmium disturbs bone formation and skeletal development, but data is scarce. In this work, zebrafish was used to further characterize the anti-osteogenic/osteotoxic effects of cadmium and gain insights into underlying mechanisms. Upon exposure to cadmium, a reduction of the opercular bone growth was observed in 6-days post-fertilization (dpf) larvae and an increase in the incidence of skeletal deformities was evidenced in 20-dpf post-larvae. The extent and stiffness of newly formed bone was also affected in adult zebrafish exposed to cadmium while regenerating their caudal fin. A pathway reporter assay revealed a possible role of the MTF-1 and cAMP/PKA signaling pathways in mechanisms of cadmium osteotoxicity, while the expression of genes involved in osteoblast differentiation and matrix production was strongly reduced in cadmium-exposed post-larvae. This work not only confirmed cadmium anti-osteogenic activity and identified targeted pathways and genes, but it also suggested that cadmium may affect biomechanical properties of bone.

An Observational Study of Skeletal Malformations in Four Semi-Intensively Reared Carp Species

“…Moreover, the most affected vertebral region in the common carp was the caudal one, whereas most of the anomalies affected the pre-haemal region in the other examined species. Except for the numerous laboratory experiments carried out to assess the effects of experimental diets (e.g., [ 46 , 47 ]) or toxic compounds (e.g., [ 48 , 49 ]) on zebrafish skeletogenesis, limited information on the occurrence of skeletal anomalies in juvenile cyprinids is available. In a comparative study on juvenile zebrafish, a higher percentage (93.4%) of reared individuals have been reported to be affected by skeletal anomalies compared with wild-caught fish (87.2%) [ 29 ].…”

Cadmium as an Endocrine Disruptor That Hinders the Reproductive and Developmental Pathways in Freshwater Fish: A Review

“…The same experiment also calculated the hatching period, which showed no or delayed hatching [115]. Similarly, 6 days post fertilization, zebrafish exposed to 25 and 125 µg/L of Cd showed detrimental effects, with reduced opercular bone growth and skeletal malformation during larval development [101].…”

Deformities in fish: A barrier for responsible aquaculture and sustainable fisheries

“…8 Exposure to tetrachlorodibenzo-p-dioxin caused cranial and axial skeleton deformities, 161 while Cd caused skeletal deformities in arches, abdominal vertebrae, caudal fin and the cephalic region of zebrafish, D. rerio. 162 Antifouling agents, such as tributyltin and triphenyltin (TPT), negatively affect embryogenesis in Japanese Medaka, O. latipes, which includes abnormal eye development, a shrunken yolk sac, delayed body development, damage of internal organs, haemorrhages and fatal heart rhythm abnormalities. 87,89 Exposure of TPT may affect egg quality and gonad development.…”