Immunotoxic Effects of Cadmium on Freshwater Crab, Sinopotamon
|Keywords||Freshwater crab (Sinopotamon) Immunotoxicity Activities of enzyme Ultrastructure Cadmium|
Acute toxicity method was used in this paper to study Immunotoxic effects of Cadmium (Cd2+) on Sinopotamon. Crabs were exposed to Cd2+ (7.25,14.5,29,58 and 116 mg/L) for 24,48,72,96 h separately. THC, DHC, and PO, SOD, ACP, AKP activity which as immunity indexes were measured subsequently. Next, Crabs were exposed to Cd2+(7.25,29,116 mg/L) for 96 h. And the technology of transmission electron microscope was used to confirm the effect on haemocyte of freshwater crabs and the activation mechanism of PO activity after cadmium (Cd2+) administration. In addition, A prelimimary study was carried out on the proPO gene. A nucleotide segment of proPO Gene was gained. The results shown as follows:First, All of THC were declined significantly relative to the control at all time points. By contrast, the proportions of three kinds of hemocyte rested at control level basically. Consequently, the change of DHC was similar to THC to a certain extent.Second, The activities of PO and SOD increased initially and decreased subsequently following the increase of concentrations of Cd2+. ACP activity changed similarly following the up of duration of treatment, while AKP activity went on increase persistently. All the results indicated that Cd2+of different concentrations and durations showed different immunity enzyme activity changes.Third, different kind of haemocyte underwent various changes following treatment with various Cd2+concentrations. The number of cytoplasmic granules decreased simultaneously in both semigranular and granular cells, while hyaline cells hold out pseudopods because of the phagocytotic ability by lower concentrations of Cd2+for 96 h. When the concentrations increased, pseudopods and lysosome contained foreign materials were observed in semigranular cells. Consequently, this kind of cell possess the phagocytotic ability.Finally, a nucleotide segment 1218 bp length was gained. After blasted in NCBI, the nucleotide segment was similar to that of Cancer pagurus. It was indicated that it was the partial homologous segment of proPO gene.Conclusions:Firstly, Cd2+could disturb haematogenous tissue which form and deposit hemocytes, subsequently result in the reduction of hemocyte number and the similar changes of THC and DHC.Secondly, The activities of PO and SOD may effectively reflect the stress to aquatic animals induced by Cd2+and could be considered as biological monitoring indexs of the pollution induced by cadmium in aquatic ecosystems.Thirdly, Cd2+could stimulate proPO system and immune function of all kinds of haemocyte respectively. In addition, the changes of all cells exhibit a concentration-response relationship. Therefore, these parameters could be considered as biological monitoring indexs of the pollution induced by cadmium in aquatic ecosystems.