Toxicity Assessment Of Quantum Dots Exposure On The Lactational Female Rat And The Offspring

In vivo toxicity of quantum dots(QDs)in animals has been broadly studied.However,its reproductive toxicity toward pregnancy and lactation animals has not yet been systematically investigated.In addition to the biological toxicity caused by heavy metal cadmium itself,nanoscale form of the QDs particle may also cause unpredictable toxic effects.Previous researches showed that QDs can accumulate in vivo and pass through placenta barrier and cause fetus death,but it is still not clear that the acute toxicity toward mother and chronic toxicity toward offspring following postpartum exposure to QDs.And whether or not QDs could enter into the breast milk and then transfer to the offspring via breastfeeding have not been reported.It is imperative to comprehensively evaluate any potential risks of QDs exposure before clinical applications.The aim of this study was to assess the toxicity toward maternal rats and offspring of postnatal exposure to QDs and its toxicokinetics in vivo.In this study,SD rats were selected as target animals,systematical evaluation of the acute and chronic toxicity of QDs exposure were performed.Body weight change,food intake,ratio of food intake/body weight,the fatality rate,viscera index,hematology and serum biochemistry,histology,and sex hormones were determined to explore the acute toxicity to mother and effects on growth and development of offspring.Furthermore,the cadmium concentrations in organs of mother and infant were measured using ICP-MS,to elucidate whether or not QDs were able to translocate to the offspring via breastfeeding.These findings showed that:l)5 nmol/rat QDs induced 33.3%rats acute death,and survival rats exhibited body weight and food consumption significantly decreased,splenomegaly,obvious tissue damage,inflammation or lesions,and endocrine disruption in comparison to control rats.In contrast,1 nmol/rat QDs caused slight toxic effects including body weight decreases,variations in serum indicators of liver and kidney functions,and mild histopathological changes.2)QDs primary accumulated in liver and spleen in day 1 after injection,while as the highest concentration stored in kidney at day 18.Furthermore,a small amount of QDs has been detected in breast milk and stomach and intestine of infant,suggesting the QDs could transmit to breast milk via blood circulation and transfer to the offspring via breastfeeding during lactation period.3)High dose QDs lead to the offspring mortality as high as 71.08%,and surviving offspring had severe growth inhibition,while no animal was death in low dose group but offspring showed distinct growth restriction within 90 days after injection.However,the hematology and serum biochemistry and histology results showed slight chronic toxicity toward offspring up to 180 days after injection.Taken together,this study investigated the reproductive toxicity of QDs in postnatal exposure,and provided the theoretical basis for the exposure assessment of QDs in lactation animals,as well as for the application or prohibition of QDs in mammals.