Study On Toxicological Effects Of PVC Microplastics On Juvenile Yellow River Carp

With the extensive use of plastic products,microplastic pollution has become one of the problems that cannot be ignored.However,little is known about the impact or potential harm of microplastics on the environment and human health.As a unique species in the Yellow River Carp,the Yellow River Carp is usually used as an animal model to assess the toxicological effects of pollutants in the aquatic environment due to its unique living habits and high economic value.In this study,first examined the effects of 10%,20%,30%,and 40% of the total dietary weight of Polyvinyl Chloride(PVC)microplastics on the growth of the Yellow River Carp,then explore the toxicological effects of PVC microplastics on the antioxidant response and immune function of carp by genetic,protein,and tissue structure levels,respectively.1.Effect on gonadal development: After 30 and 60 days of continuous exposure to different concentrations of PVC microplastics,the expression changes of gonadal development genes in liver and gonadal tissues were detected,and the effects of PVC microplastics on the tissue structure of gonadal tissues of Juvenile Yellow River Carp were observed.The results showed that the expression of gonadal developmentgene estrogen receptor(ERα),vitellogenin(Vtg I),and choriogenin(Chg H)in liver and gonad of female and male Yellow River Carp after exposure to PVC microplastics.There are varying degrees of change,and the change trend was also different.Abnormal proliferation of germ cells was also observed in testis sections exposed to 10% PVC microplastics.2.Effect of anti-oxidation: After exposure to PVC microplastics,we selected liver,intestine and gill to detect the expression of antioxidant enzyme-related genes and enzyme activities.The results showed that the activities of Superoxide Dismutase(SOD),Catalase(CAT)and Glutathione Peroxidase(GPx)were increased in the low concentration group and decreased in the high concentration group compared with the control group.The levels of malondialdehyde(MDA)in the liver,intestine and gill of the Juvenile Yellow River Carpr were significantly reduced after exposure in addition to a significant increase in the 40% concentration of the treatment group in the liver.The expression levels of antioxidant related genes CYP1 A,GSTpi and GSTa were the same as those of antioxidant enzyme activities.By HE staining,microplastics were observed in the liver of the Yellow River Ccarp exposed to PVC microplastics to induce changes in tissue structure such as cytoplasmic vacuolation,inflammatory cell infiltration and nuclear disappearance.3.Effect on immune function: After exposure of PVC microplastics to Juvenile Yellow River Carpr,we first detected the expression of three immune-related genes,complement C3,interferon gamma(INFγ)and interleukin-1β(IL-1β),in liver,intestine and gill.The results showed that INFγ and IL-1β were significantly up-regulated in the liver of juvenile Yellow River Carp in the 10% and 30% treatment groups after 60 days of exposure.The expression of complement C3 in the intestine of juvenile Yellow River Carp larvae first decreased and then increased,while the expression increased first and then decreased in the gill.Secondly,the activities of Acid Phosphatase(ACP),Alkaline Phosphatase(AKP)and Lysozyme(LZM)were detected.The activity of AKP and ACP was significantly decreased in the liver and intestine compared with the control group,but it was significantly increased in the 10% treatment group in the gill.The content of LZM generally increased.Finally,the level of immunocytokines interleukin-6(IL-6),interleukin-8(IL-8)and tumor immune factor ɑ(TNFɑ)in the liver of juvenile Yellow River Carp were detected by Elisa technique.The results showed that the level of the three cytokines increased significantly after 30 days of exposure,and decreased with the prolongation of exposure time.The above studies showed that PVC microplastics inhibited the normal growth of juvenile Yellow River Carp,disrupted the expression of genes involved in gonadal development and organization,and induced oxidative damage and changes in immune system function.These results from different research levels can provide valuable biological references for the toxicological effects and risk assessment of microplastics.