Effects of zearalenone on calcium homeostasis of splenic lymphocytes of chickens in vitro.

Zearalenone (ZEA) is an estrogenic my-cotoxin. It is produced by several Fusarium species and can contaminate food and feed. To investigate the role of calcium homeostasis in ZEA-induced toxicity of poultry and elucidate its cytotoxic mechanism, splenic lymphocytes isolated from chickens were exposed to ZEA (0-25 pg/mL) for 48 h. The intracellular calcium concentration ([Ca +]i), pH, calmodulin (CaM) mRNA levels, and Na+/K+-ATPase activities and Ca2+-ATPase activities were detected by the fluorescent dyes Fluo-3/AM and BCECF/AM, quantitative real-time PCR, and chromatometry. Supernatant CaM concentrations were simultaneously detected by ELISA. As the ZEA exposure concentration increased, the [Ca2+] i and CaM mRNA levels gradually increased, while in-tracellular pH, CaM concentrations of supernatants, and intracellular Na+/K+-ATPase and Ca2+-ATPase activities gradually decreased in a dose-dependent man-ner. There were significant differences (P < 0.05 or P < 0.01) between the treatment groups and the control group. These results indicate that ZEA cytotoxicity arises by causing an imbalance in calcium homeostasis and intracellular acidification in lymphocytes. [ABSTRACT FROM AUTHOR]