Influence of heavy nanocrystals on spermatozoa and fertility of mammals

In recent years, quantum dots (QDs) have been widely used in upcoming nanotechnology-based solar Cells, light emitting diodes and even bioimaging, due to their tunable optical properties and excellent quantum yields. But, such nanostructures are currently constituted by heavy elements which can threat the human health and living environment. Hence, in this work, the in vivo effects of CdTe nanocrystals (NCs) (as one of the promising QDs) on spermatozoa of male mice and subsequently on fertility of female mice were investigated, for the first time. To do this, CdTe NCs were synthesized through an environment-friendly (aqueous-based solution) method. The sperm cells presented a high potential for uptake of the heavy QDs. Meantime, the NCs exhibited concentration-dependent adverse effects on morphology, viability, kinetic characteristics and DNA of the spermatozoa. At low concentration of 0.1 mu g/mL, the NCs showed a moderate toxicity (similar to 25% reduction in viability and motility of the spermatozoa), while remarkable toxicities were observed at higher concentrations of 1.0-100 mu g/mL (similar to 67% reduction in viability and mobility for 100 mu g/mL). Furthermore, significant in vitro DNA fragmentation of the spermatozoa was observed at CdTe concentrations >= 10 mu g/mL. In vivo toxicity of the NCs was found lower than the in vitro toxicity. Nevertheless, the In vivo destructive effects of the NCs still caused similar to 34% reduction in viability as well as motility and similar to 5% damages in DNA of male mice spermatozoa. These resulted in similar to 26% decrease in fertility and gestation of female mice, along with an overall hormone secretion during the pregnancy, and similar to 39% reduction in viability of pups/pregnant females. (C) 2016 Elsevier B.V. All rights reserved.