Hepcidin and iron metabolism in non-diabetic obese and type 2 diabetic rats

The aim of this study was to investigate the changes of iron levels and hepatic regulatory molecules expression involved in iron metabolism in non-diabetic obese/type 2 diabetic rat models. Male Wistar rats were divided into 3 groups: control group, non-diabetic obese group and type 2 diabetic group (n=20 each). The rats were evaluated physiologically and biochemically. The hepatic histopathological changes were observed using haematoxylin and eosin (HE) staining. The mRNA expression patterns of hepcidin, interleukin-6 (IL-6), hypoxia-inducible factor (HIF) and ferroportin (Fpn) in the rat liver in control group, non-diabetic obese group and type 2 diabetic group were analyzed by real-time RT-PCR. The protein expression patterns of hepcidin in liver of each group were further analyzed by immunohistochemistry and Western blotting. As compared with control group, the ferritin in non-diabetic obese group and type 2 diabetic group was increased significantly (P<0.001). However, there was no significant difference in soluble transferring receptor (sTfR):ferritin ratio among the three groups (P>0.05). The real-time RT-PCR, immunohistochemistry and Western blotting results all revealed that the expression levels of hepcidin in non-diabetic obese group and type 2 diabetic group were elevated significantly as compared with those in control group (P<0.001). The expression levels of hepcidin mRNA between non-diabetic obese group and type 2 diabetic group showed no significant difference (P>0.05). However, the protein expression levels of hepcidin in type 2 diabetic group were significantly higher than those in non-diabetic obese group (P<0.05). Compared to control group, the expression levels of IL-6 mRNA in non-diabetic obese group and type 2 diabetic group were increased significantly and the expression levels of Fpn mRNA decreased (P<0.05). However, the expression levels of HIF mRNA had no significant difference among three groups. It is suggested that iron metabolism is substantially disturbed in non-diabetic obese and type 2 diabetic rats probably by the abnormal expression of hepcidin in chronic inflammatory status. The increased hepcidin may restrain the iron release from the cells by affecting the expression of Fpn, which probably associates with the development of diabetic complication.