Prenatal and maternal study of halloysite toxicity in pregnant rats

Halloysite nanoclay (HNC) is a naturally occurring tubular aluminosilicate that has various applications in nanotechnology and drug delivery. However, its toxic effects during gestation are inadequately reported. This study assessed the maternal and fetal toxic effects of intranasally and orally administered HNC. Pregnant rats were divided into three groups: vehicle control, oral HNC (75 mg/kg), and intranasal HNC at the same dose from day 0 to day 19 of gestation (day after day). Dams showed weight loss, but HNC did not cause lethality in both groups. HNC reported route-dependent tissue toxicity. Orally administered HNC leads to more pronounced oxidative intestinal damage than intranasal treatment. Intranasal administration has a much greater impact on reducing thiol content in the lungs compared to oral administration. Histopathological analysis revealed that the fetal pancreas of dams treated with HNC intranasally showed marked necrotic acini and congested blood vessels, whereas the dams treated orally exhibited foamy macrophages and lung angiopathy more frequently than the intranasally treated ones. These results highlighted that HNC, at the tested dose, caused significant pathological and oxidative damage to maternal and fetal tissues.