Developmental Toxicity And Mechanisms Caused By Cefixime In The Otic Vesicles Of Zebrafish Embryos Or Larvae

Cefixime(CE)is a third-generation cephalosporin drug,which is widely used clinically because of its high efficiency and low toxicity.However,the developmental toxicity of CE on embryos,especially the effect on ear follicle development,remains to be studied in depth.In this study,zebrafish embryos were used as animal models to explore the toxic mechanism of CE-induced ear follicle development disorders in zebrafish embryos.Exposure to zebrafish embryos 4 hours(4hpf)after fertilization with different concentrations of CE(0-100μg/m L)will affect the development,behavior,cartilage development,and ear vesicle development related genes of zebrafish juveniles And changes in protein levels were detected.The results showed that when the embryo developed to 96 hpf,with the increase of CE concentration,it caused a significant increase in zebrafish embryo mortality and a significant decrease in hatching rate(p<0.05).When the embryo developed to 120 hpf,100μg/m L CE caused a significant reduction in the swimming distance of the juvenile fish(p<0.05),and Fgf8a inhibitors and BMP inhibitors caused similar behavioral changes.Interestingly,we first found that CE significantly reduced the area of the balloon and utricle and the area of ear vesicles in juvenile zebrafish(p<0.001).Fluorescence staining with2-[4-(Dimethylamino)styryl]-1-ethylpyridinium iodide(DASPEI)showed that with the increase of CE concentration,the fluorescent spots of zebrafish lateral hair cells decreased significantly.The expression of bone-related genes was detected by RT-qPCR.At 72 hpf and 120 hpf,CE caused the down-regulation of cartilage and hard bone-related genes(Fgf8a,Sox9a,Sox9b,Col2α1a,Col1a1,Bmp4,runx2a,Dlx2a,and eya4).It also caused a significant down-regulation of the expression of Na~+/K~+-ATPase-related genes such as atp1a2,atp1a3b,and atp1b2b.In addition,compared with the control group,100μg/m L CE also caused a decrease in Na~+/K~+-ATPase activity(p<0.01).Further antibody staining also verified that CE significantly reduced the expression of Na~+/K~+-ATPase protein.Experimental results show that cefixime has a significant toxic effect on zebrafish embryo development,especially ear development disorders,which are closely related to Na~+/K~+-ATPase.The experiment also provides new detection indicators for the research on the detection of feed drug contamination and residues.