Does Hepatic Hepcidin Play an Important Role in Exercise-Associated Anemia in Rats?

Some athletes are diagnosed as suffering from sports anemia because of iron deficiency, but the regulatory mechanism remains poorly understood. It is reported that hepcidin may provide a way to illuminate the regulatory mechanism of exercise-associated anemia. Here the authors investigate the hepcidin-involved iron absorption in exercise-associated anemia. Twelve male Wistar rats (300 +/- 10 g) were randomly divided into 2 groups, 6 in a control group (CG) and 6 in an exercise group (EG, 5 wk treadmill exercise of different intensities with progressive loading). Serum samples were analyzed for circulating levels of IL-6 by means of enzyme-linked immunosorbent assay (ELISA). The expression of hepatic hepcidin mRNA was examined by real-time polymerase chain reaction analysis. The protein levels of divalent metal transporter 1 (DMT1), ferroportinl (FPN1), and heme-carrier protein 1 (HCP1) of duodenum epithelium were examined by Western blot. The results showed that the amount of iron and ferritin in serum were lower in EG than in CG (p < .05). The levels of IL-6 and white blood cells were greater in EG than in CG (p < .01). The expression of DMT1, HCP1, and FPN1 was significantly lower in EG than in CG (p < .01). The mRNA expressions of hepatic hepcidin and hemojuvelin in skeletal muscle were remarkably higher in EG than in CG. The data indicated that inflammation was induced by strenuous exercise, and as a result, the transcriptional level of the hepatic hepcidin gene was increased, which further inhibited the expression of iron-absorption proteins and led to exercise-associated anemia.