Ca²⁺-ATPase and metallothionein expressing induced by cadmium in the primary cultured hepatocytes of crucian carp(Carassius auratus)

Cadmium is one of environment heavy metal pollutants which is ranked the eighth in the top toxic substances harmful to human health by the Agency for Toxic Substances and Disease Registry(ATSDR).Cadmium is easy to be absorbed by aquatic organisms and to be deposited in the body.We studied the performance of the Ca²⁺-ATPase and metallothionein in primary cultured hepatocytes of Carassius auratus.Hepatocytes were incubated with cadmium chloride at 5,10,15 and 20 μmol/L for 24 h.Fluo-2/AM fluorescent labeling is used to show the Ca²⁺ level.The activity of Ca²⁺-ATPase was measured by spectrophotometry graphite,cadmium by atomic adsorption spectroscopy and metallothionein(MT)by ELISA.Fluorescence intensity of Ca²⁺ was higher in the treatment groups than in control group; the activity of Ca²⁺-ATPase was significantly increased(P＜0.01).Ca²⁺-ATPase activity in treatment group were 4.52,6.73,6.68,7.19,6.18 times higher than that in the control group respectively.MT expression level was significantly increased in each treatment group(P<0.01),and MT content of 5 μmol/L group increased by 17.15 %(P＜0.01).The results indicate that cadmium increases levels of Ca²⁺ and MT in hepatocytes of Carassius auratus,and MT chelated cadmium in hepatocytes,which may be one of the mechanisms that reduce the cadmium toxicological influence.