Detection Of Apoptosis Of Gill Cells Induced By Cadmium And Mechanism Of Action Of Metallothionein

Acute toxicity was used to expose the clams to different concentrations of Cd²⁺?0,1.5,3,6,12 mg/L?for 5 days.Morphological,biochemical,and molecular biological methods and methods were used to detect Cd²⁺on the cells of the clams.The degree of death and the role of metallothionein?MT?.The results showed that with the increase of Cd²⁺concentration,the number of DNA trapezoidal bands increased and became clear;after AO/EB double fluorescent staining,the cells transitioned from green to orange or even red,and the rate of apoptosis increased continuously.Cd²⁺produced damage to the tussock silk,the sacral pipe,and the sacral epithelium.With the increase of Cd²⁺concentration,the cell deformed and membrane vesicles became severely vacuolated,mitochondrial ridges decreased,and lysosomes appeared.The ROS content and DNA-protein cross-linking ratio?DPC?in sputum increased with the increase of Cd²⁺concentration,showing a concentration-dose effect relationship,but the protein carbonyl?PCO?content increased first and then decreased with the increase of Cd²⁺concentration.The activities of Caspase-3,8,9 in each Cd²⁺contaminated group were significantly activated.With the increase of Cd²⁺concentration,the activity of SOD,CAT,GPx and the expression of MT mRNA both increased first and then decreased.The ultra-trace of Na⁺-K⁺,Ca²⁺-Mg²⁺and total ATPase activity were slightly inhibited.The expression of MT mRNA was highly correlated with PCO and significantly correlated with Caspase-3.Cadmium can cause a large number of free radicals in the clam cell,which causes damage to the cell membrane structure,especially the mitochondrial structure,and affects normal physiological functions,resulting in oxidative damage and even apoptosis.MT can regulate the change of PCO content and can regulate the role of Caspase-3 gene in mitochondria-mediated endogenous apoptosis pathway.