A preliminary study on changes in heat shock protein 70 levels induced by Fusarium mycotoxins in rats: in vivo study.

The heat shock protein (Hsp70) level was assessed after 14 days of oral gavage-exposure to fumonisin B1 (FB1: 150 µg/animal/day), deoxynivalenol (DON: 30 µg/animal/day) and zearalenone (ZEN: 150 µg/animal/day), alone or in combinations (in additive manner: FD = FB1 + DON, FZ = FB1 + ZEN, DZ = DON + ZEN and FDZ = FB1 + DON + ZEN) in the liver, kidneys and lung of 24 adult male Wistar rats (n = 3/group). The liver was the most responsive tissue, as compared with kidney and lung. Except of DZ-treatment, mycotoxins elevated the Hsp70 levels in livers. The highest Hsp70-levels (≈ twofold) were in the DON, FD, FZ and FDZ treatments (additive effects). In the kidney, alterations (↑ ≈ twofold) were detected in ZEN, FD, FZ and DZ treatments. The least responsive organ was the lung (↑ only in FDZ, antagonistic effect). DON and ZEA exposures have altered the reduced glutathione concentration (↓) and glutathione peroxidase activity (↓) in the blood serum. The serum malondialdehyde level increased only after exposure to FD (synergistic effect), as compared with the DZ group (antagonistic effect). When the blood clinical chemistry was assessed, significant alterations were in alanine aminotransferase (80% increase in FDZ, antagonistic effect) and total protein (↓ ZEN). Results varied according to the organ, toxin type and interactions. Furthermore, oxidative stress was not the only key player behind the Hsp70 increase, in which another mechanism is suggested.

Fumonisin B1 exposure increases Hsp70 expression in the lung and kidney of rats without inducing significant oxidative stress.

The objective of this experiment was to determine whether fumonisin B1 (FB1) added to the diet of rats in a dose of 50 mg/kg changes the production of heat shock protein 70 (Hsp70) in the lungs and kidney of rats. We also studied the effect of this mycotoxin on the antioxidant system of the body. Mature (8 weeks old) male Wistar Crl:WI BR rats (n = 6/group) were fed the toxin-containing diet for 5 days. FB1 resulted in a 7% body weight reduction without significantly changing the feed intake. Western blot analysis of the lungs and kidney demonstrated a substantial (1.4-fold and 1.8-fold, respectively) increase in Hsp70 expression. Alterations could not be detected in the clinical chemical parameters (total protein, albumin, total cholesterol, glucose, creatinine and urea concentrations, and aspartate aminotransferase activity). There was no statistically significant change in malondialdehyde concentrations and the measured antioxidant parameters (the amount of reduced glutathione, GSH and glutathione peroxidase activity, GPx) in the blood plasma, lung and kidney tissue. Thus, it can be concluded that FB1 did not induce oxidative stress in the lungs and kidney, but increased Hsp70 production.