Reproductive And Genotoxic Toxicity Of ZnSe/ZnS Quantum Dots On Rare Minnow(Gobiocypris Rarus)

Quantum dots have shown good application prospects in various fields of scientific research,and their applications are more and more extensive.Compared with other studies of quantum dots,their physiological toxicity research is relatively scarce.Therefore,the environmental pollution and biosafety problems caused by quantum dots have attracted more and more attention from scholars at home and abroad.Compared with Cd quantum dots,ZnSe/ZnS quantum dots do not contain heavy metal elements,but whether they are safer than Cd quantum dots and do harm to organisms is unknown,so it is necessary to study their biological toxicity.In this study,Gobiocypris rarus was used as material.The purpose of this study was to investigate the effects of ZnSe/ZnS quantum dots on the reproductive system of parents and the growth and development of offspring.The results reveal the genotoxicity of ZnSe/ZnS quantum dots,provide basic information for the biological safety assessment of ZnSe/ZnS quantum dots,and provide theoretical basis for their utilization and promotion.In experiment I,This research sets five ZnSe/ZnS quantum dots concentrations treatments,50,100,10,200,400,800nmol/L and an control group.The effects of different concentrations of ZnSe/ZnS quantum dots on gonad structure,reproductive related genes(AR,ER,Dmrt1),sperm viability,semen DNA damage and sperm DNA repair related genes(Xrcc1)were detected.In experiment II,the effects of different concentrations of ZnSe/ZnS quantum dots on morphological/behavioral parameters,antioxidant enzyme activity and MDA content,DNA damage and expression of DNA damage repair gene Xrcc1 in F1 embryos of Gobiocypris rarus were studied at 12,24,48,72 and 96 hpf.The male-female ratio and growth index of adult fish were measured.The results of reproductive toxicity of ZnSe/ZnS quantum dots on Rare Minnow showed that the sperm structure of Rare Minnow would be damaged after treatment with ZnSe/ZnS quantum dots.The high concentration group showed different degrees of non-cellular area enlargement and reduction of germ cells.In addition,the sperm of800 nmol/L concentration group also had cavity after loss of germ cells,which had no obvious effect on ovarian structure.The transcription levels of AR and Dmrt1 genes related to spermatogenesis in testis were significantly decreased.In addition,ZnSe/ZnS quantum dots also inhibit the expression of Xrcc1,a representative gene of sperm DNA damage repair,resulting in sperm DNA damage and reduced sperm viability.The toxicity of ZnSe/ZnS quantum dots on the growth and development of F1 generation of Rare Minnow showed that after exposure to ZnSe/ZnS quantum dots,many toxic symptoms appeared in F1 generation embryos,such as spine curvature,tail curvature,pericardial edema and yolk deformity.The frequency of spontaneous movement and heart rate were slowed down,the hatching time of embryos was changed,and the hatching rate was reduced.SOD,CAT,GSP-Px antioxidant enzyme activity and MDA content were compared with the control group.Compared with the control group,there was an increase in unnecessary degree,and DNA damage and DNA repair related gene Xrcc1 expression decreased in the high concentration group.In addition,the proportion of female adults in F1 generation increased after exposure to ZnSe/ZnS quantum dots,and the total length,body length,body height and body weight increased to a certain extent compared with the control group.The lower the concentration,the more obvious the increase.The results showed that exposure to ZnSe/ZnS QDs resulted in changes in sperm structure,down-regulation of sperm reproduction-related genes and DNA repair-related genes,DNA damage of sperm and decrease of sperm motility.The secondary malformation,oxidative stress,down-regulation of DNA damage and repair-related genes of F1 embryos.Changes in sex ratio and down-regulation of growth index in F1 generation.