Effects Of Aroclor 1242 On The Liver Of Carp

Polychlorinated biphenyls?PCBs?are chlorides formed by the substitution of a hydrogen atom on a biphenyl benzene ring by chlorine,and are widely used industrially.PCBs are extremely difficult to decompose,and have strong fat solubility.They are easily enriched in organisms and have carcinogenic,teratogenic and mutagenic effects.They are a class of persistent organic pollutants that are of common concern at home and abroad.In this paper the selected agents are non-distilled PCBs with about 42%chlorine?Aroclor1242?,and the subjects are China's important freshwater economic fish species?Cyprinus carpio?.The acute toxicity effect of Aroclor1242 on the carp was revealed by static water exposure.The response of the main biomarkers of the liver tissue of the carp was exposed to Aroclor1242.The accumulation of Aroclor1242 in the liver of the carp and the microstructure of the liver tissue of the carp were studied.And changes in ultrastructure.1.According to the results of acute toxicity test,the median lethal concentration(LC₅₀)of the carp Aroclor1242 was 800?g/L,which was a highly toxic substance.2.Through the subacute toxicity test,the oxidative stress of liver cells of the carp was observed under the exposure of Aroclor1242:the ROS content increased with the increase of Aroclor1242 concentration;superoxide dismutase?SOD?,peroxidase?POD?,catalase?CAT?,glutathione S-transferase?GST?,glutathione?GSH?,glutathione peroxidase?GSH-Px?activity or content is basically"hormesis effect",and to some extent,the time dose effect;with the increase of Aroclor 1242concentration,the malondialdehyde?MDA?content in the liver tissue of the carp increased significantly,indicating that membrane lipid peroxidation has occurred and the membrane system is damaged.In addition,Caspase-3 activity also increased with the increase of Aroclor1242 exposure concentration,which means that liver tissue cells may have apoptosis.3.The accumulation of Aroclor1242 in the liver tissue of the carp was analyzed by gas chromatography.The presence of Aroclor1242 was detected in the liver of the carp after exposure to Aroclor1242 solution for 10 days,and the content of Aroclor1242 in the liver increased with the increase of exposure concentration.Explain that Aroclor1242 accumulates in the liver.4.Liver paraffin sections were observed.After exposure to Aroclor 1242 solution for 15 days,the liver tissues and organs of the carp showed different degrees of damage.As the concentration of Aroclor 1242 increases,liver cell damage is intensified,and nuclear deformation and pyknosis,nuclear lysis,and cytosolic vacuolization can be observed.5.Observing the liver transmission electron microscope,100?g/LAroclor1242 exposed for 24d,it will damage the liver cell structure of the carp.The nucleus of the liver cells of the carp was deformed,the mitochondria were deformed and the number was reduced,and some of the hepatocytes were vacuolated.After exposure to 400?g/LAroclor1242 for 24d,the nucleus of the liver cells of the carp was lysed and condensed and deformed.The endoplasmic reticulum is enlarged,the number of lipid droplets is increased,and the phenomenon of cell vacuolization is intensified.