A Study Of Single And Union Poisoning Of Cadmium And Chlorpyrifos Caused Autophagy In Common Carp Livers

Cadmium?Cd?is one of the toxic heavy metals that is widely used in industrial manufacture and daily life.Chlorpyrifos?CPF?is one of the most commonly used organophosphate pesticides in agricultural production.Cd and CPF could cause environmental pollution,and accumulate in human beings'and animals'bodies via polluted air,soil,water,and food,thus affect their health.The liver is one of the target organs of Cd and CPF.The aim of this research was to investigate the harmful effect of single and union poisoning of Cd and CPF on livers of common carp,an aquatic organism,and to provide basic datum for Cd and CPF single and union poisoning resulting in autophagy of common carp livers,providing reference for the effect of Cd and CPF on single and union poisoning of common carp livers.One hundred and twenty healthy common carps were randomly divided into four groups:the control group,the Cd group,the CPF group,and the Cd/CPF group.The carps in the control group were fed in dechlorinated tap water?DTW?.The carps in the Cd group were fed in CdCl₂·2.5H₂O-added DTW?containing 0.26 mg/L Cd?.The carps in the CPF group were fed in CPF-added DTW?containing 14.5?g/L CPF?.The carps in Cd/CPF group were fed in CdCl₂·2.5H₂O/CPF-added DTW?containing 0.26 mg/L Cd,14.5?g/L CPF?.Each group was fed with standard granulated diet every day.On the 15^th,30^th,and 45^th days of the experiment,6carps in each group were randomly selected and anatomized.The livers were then removed immediately.The following examinations were carried out:microstructural and ultrastructural observation,antioxidant indicators?contents of H₂O₂,MDA,GSH,activities of CAT,SOD,GPx,GST,and T-AOC?,mRNA expression of autophagy-related genes?TOR,LC3-II,Beclin 1,Dynein,ATG12,and ATG5?in common carp livers.The results showed as follows:?1?Single and union poisoning of Cd and CPF induced changes of morphology in common carp livers.Microstructural changes included hepatocyte vacuolization,nucleus density,cytoplasmic concentration,hepatocyte necrosis,disorder arrangement,and erythrocyte exudation.Ultrastructural changes included hepatocyte nucleus,membrane fusion,mitochondria vacuole,chromatin condensation,and autophagic vacuole.Single and union poisoning of Cd and CPF caused common carp livers injury and autophagy.The degree of liver injury and autophagy in the Cd/CPF group was stronger than that of Cd group and CPF group,and thus,Cd and CPF had a union poisoning effect.?2?Single and union poisoning of Cd and CPF increased the H₂O₂ and MDA contents,decreased GSH content,and inhibited CAT,SOD,GPx,GST,and T-AOC activities in common carp livers.Compared with the Cd and CPF group,H₂O₂ and MDA contents in the Cd/CPF group were significantly increased.Compared with the Cd group and CPF group,GSH content,CAT,SOD,GPx,GST,and T-AOC activities in the Cd/CPF group were significantly decreased.Single and union poisoning of Cd and CPF caused oxidative stress in the common carp livers.The oxidative stress of common carp livers in the Cd/CPF group were stronger than that of Cd group and CPF group.It could be safely concluded that Cd and CPF had a union poisoning effect.Moreover,the activities of H₂O₂ in the Cd/CPF group,the activities of CAT in the Cd group and CPF group and Cd/CPF group had a time-dependent manner.?3?Single and union poisoning of Cd and CPF inhibited TOR mRNA expression,and induced the mRNA expression of LC3-II,Beclin 1,Dynein,ATG12,and ATG5.TOR mRNA expression in the Cd/CPF group were significantly decreased comparing to the Cd group and CPF group.LC3-II,Beclin 1,Dynein,ATG12,and ATG5 mRNA expression of the Cd/CPF group are much higher than that of Cd group and CPF group.Single and union poisoning of Cd and CPF caused autophagy in the common carp livers.The degree of single and union poisoning of Cd and CPF on autophagy was stronger than that of Cd group and CPF group,and it indicated that Cd and CPF had a union poisoning effect.Moreover,in the Cd group,CPF group,and Cd/CPF group,TOR and ATG12 mRNA expression,LC3-II mRNA expression in the Cd group,Beclin 1,Dynein,and ATG5 mRNA expression in the Cd/CPF group had a time-dependent manner.Single and union poisoning of Cd and CPF caused autophagy via oxidative stress in common carp livers.Cd and CPF had a union poisoning effect.