The Ecotoxicological Effects Of Dibutyl Phthalate On The Zebrafish(Danio Rerio)

Phthalates?PAEs?are one of the most commonly used plastic additives in industry to make plastics soft and flexibility,which have been widely used in the world.Because they are not chemically bonded to plastic polymers,they can easily migrate from plastic products to the environment,causing human exposure to phthalates via ingestion,inhalation,skin contact and so on.Phthalates are not easy to degrade and can be enriched in human body.Phthalates and their metabolites have potential risk to human body.Dibutyl phthalate?DBP?is one of the most commonly used phthalates.DBP can be frequently detected in soil,water,atmosphere and other environmental media,especially in the aquatic environment,causing potential risks to the aquatic organisms.Therefore,it is extremely essential to evaluate the toxicological effects of DBP on aquatic organisms to ensure the healthy development of aquatic environment.In order to explore the toxicological effects of DBP on aquatic organisms,zebrafish was used as test organism and DBP was used as the pollutant.Zebrafish were treated with blank control,acetone control,0.08,0.4,2 mg·L^-11 DBP solution for a 28-day period,the liver and brain were collected on the 7^th,14^th,21^st,28^th day.The activities of superoxide dismutase?SOD?and catalase?CAT?,and the content of reduced glutathione?GSH?were determined to investigate the damage of the antioxidant system and the malondialdehyde?MDA?content was measured to detect the degree of lipid peroxidation.The activity of acetylcholinesterase?AChE?is measured to estimate damage of nervous system and the content of 8-hydroxydeoxyguanosine?8-OHdG?was determined to evaluate DNA damage.Relative expression level of antioxidant genes?Cu/Zn-sod,gpx?and apoptotic genes?Caspase-3,p53?were determined by RT-qPCR.Finally,the toxicity of DBP to the zebrafish liver and brain were evaluated quantitatively using an integrated biomarker response?IBR?index.The main research contents and results were as follow:?1?The effect of different concentration of DBP on the enzyme activity of zebrafish was measured.The activity of SOD and CAT in the liver ware increased at first,and reduced obviously on the 28^th day.In the brain,the activity of SOD and CAT display a trend of inhibition-activation-inhibition with time.?2?Lipid peroxidation and DNA damage of zebrafish were determined with different concentration of DBP.The contents of MDA in liver and brain were significantly higher than those in the control group on the 28^th day.At the same time,the DNA damage in liver and brain had the similar trend.The 8-OHdG content in the liver and brain increased obviously on the21^st and 14^th respectively,and recovered to the control level on the 28^th day.?3?The effect of DBP on the nervous system of zebrafish was measured.The stimulation of AChE activity in the brain was more obviously than the liver,presented a trend of inhibition-activation-inhibition with time in the brain.The AChE activity of treatment groups was significantly lower than that of control on the 28^th day and the nervous system was disordered in the brain.But in the liver,the AChE activity was always activated.?4?At the molecular level,the expression of oxidative stress and apoptotic genes in zebrafish was measured by quantitative fluorescence real-time PCR DBP could cause different degree of activation to the expression of antioxidant gene?Cu/Zn-sod?gpx?in the liver and induce oxidative damage.Due to a long time of DBP stress,apoptosis-related genes?Caspase-3,p53?were significantly activated on the 28^th day.The expression of Cu/Zn-sod gene in the brain showed a trend of inhibition-activation-inhibition with time,which was consistent with the change of SOD activity.It was significantly activated on the 14^th day,and remarkably inhibited on the 28^thh day.