How cadmium and copper change the sensitivity of the hemocytes of Steatoda grossa spider on immunostimulation: qualitative and quantitative analysis

The purpose of this study was to evaluate the sensitivity of hemocytes of adult Steatoda grossa females to cadmium and copper administered orally for 4 weeks or 12 months, and to check the metabolic condition of these cells after immunostimulation with phorbol 12-myristate 13-acetate (PMA). The viability of hemocytes (flow cytometry and luminescence techniques), their ultrastructure (transmission electron microscopy), and the antioxidant activity of hemolymph (superoxide dismutase, catalase, total antioxidant capacity; TAC) were analyzed. The results showed that, compared to copper, cadmium caused severe necrotic changes in hemocytes and impaired oxygen burst reactions and antioxidant responses, regardless of the exposure time. Copper induced degenerative changes only during short-term exposure, but its long-term intoxication did not impair the metabolic processes of hemocytes. Administration of PMA to spiders that were chronically exposed to either of the metals caused an increase in TAC levels in the hemolymph. Although the concentration of ATP in hemocytes was reduced relative to the control, the ADP/ATP ratio did not change, precluding a strong depletion of cellular energy resources. The metabolic condition of hemocytes stabilized with prolonged metal exposure, indicating the activation of defense mechanisms under operating stressors.