BACKGROUND AND OBJECTIVE: Arsenic causes congenital anomalies in humans and animals, and nanoparticles of sodium arsenite are highly capable of inducing apoptosis. Since the effects of nanoparticles of sodium arsenite on fetal malformations have not been evaluated yet, this study aims to compare the effect of sodium arsenite and nanoparticles of sodium arsenite on skeletal malformations in rat embryos.

METHODS: This in-vitro study was performed on four groups of pregnant rats (n= 23 rats). Mating was confirmed by observation of vaginal plug. On the tenth day of gestation, pregnant rats in different groups received intraperitoneal normal saline (n=7 rats), sodium arsenite (11 mg/kg) (n=5 rats), nanoparticles of sodium arsenite (1 mg) (n=5 rats) and nanoparticles of sodium arsenite (11 mg) (n=7 rats). All the rats were euthanized on the twentieth day of pregnancy and their embryos were removed, their weight and length were measured, and then were stained with alizarin red and alcian blue. The skeletal system abnormities of embryos such as cleft palate, malfunctions or malformations in ribs, vertebrae, spine, sternum, arms, legs, fingers and reduction of ossification were evaluated by a stereomicroscope, and then compared with the control group.

FINDINGS: Sodium arsenite and nanoparticles of sodium arsenite reduced fetal weight from 5 g in the control group to 2 g (p≤0.033) and also, decreased fetal length from 38 cm to 28 cm in the control group (p≤0.023). The weight and length of fetuses were significantly reduced in nanoparticles of sodium arsenite group (11 mg), as compared to sodium arsenite group (p≤0.033). There were no skeletal malformations in the control group, while the percentage of anomalities was between 3% and 47% in the intervention group.