Cadmium-induced splenic lymphocytes anoikis is not mitigated by activating Nrf2-mediated antioxidative defense response.

Cadmium (Cd) is a widely used heavy metal which is reported to exert extensive harm to the environment and human health. Owing to Cd being an element it is continuously enriched in the environment. The mechanism of splenic toxicity by Cd, however, is not yet clear. In order to explore the toxic mechanism of Cd exposure to the spleen, we added 0, 35, 70 and 140 mg/kg of Cd to the diet of chicken and fed them this diet for 90 days. Analysis of histopathological sections showed that Cd exposure damaged the spleen structure, the spleen red pulp, the white pulp boundary disappeared and the number of lymphocytes decreased significantly, suggesting that Cd exposure leads to organ injury to the spleen. Particularly, Cd-induced anoikis - a special form of programmed cell death caused by the loss of contact between cells and extracellular matrix and other cells - is associated with integrin-related cell detachment and activation of apoptotic signaling pathways. Moreover, Cd exposure leads to an increase in free radicals content and affects the activity of antioxidant enzymes resulting in oxidative stress. Simultaneously, Cd activated the body's antioxidant defense system mediated by the Nuclear factor related factor 2 (Nrf2) signaling pathway. Based on our results Cd-induced splenic lymphocytes anoikis is not mitigated by Nrf2-mediated antioxidative defense response.