No abstract

Background: Iron plays a key role in biological metabolism as an essential microelement. Excess iron may cause pathological damage to the body. The purpose of this work is to explore the disorders of major inflammatory factors and histopathological lesions in the liver of excess-iron-fed sheep. Twenty German Mutton Merino sheep were randomly divided into 4 groups, control group (CON), iron-excess group one (IronE1), iron-excess group two (IronE2) and iron-excess group three (IronE3), respectively. Each group was fed with basal diets supplemented with 50 (CON), 500 (IronE1), 1000 (IronE2), and 1500 (IronE3) mg/kg as ferrous sulfate monohydrate (FeSO4 ·H2O). After 75 days, the liver was removed and collected. A variety of methods were utilized to detect indicators of sheep liver. Results: The histopathological damage of liver in sheep was rather severe with the excess of iron. Hemosiderin deposits were also obviously discovered. The results also showed that the expression of both protein and mRNA of IL-1β, TNF-α and IFN-γ reduced, but the factors of IL-2, IL-6, NF-κB and TGF-β1 obviously increased in the liver of each iron excess group. Corresponding changes were also discovered with the addition of iron dosage. The content of inflammatory factors above showed a significant change with an addition of 1500 mg/kg iron into the basic diet, which indicated that excess iron inhibited the release of IL-1β, TNF-α and IFN-γ in the sheep liver. The inflammation caused by excess iron extenuated by reducing the content of these three pro-inflammatory factors. The expression of IL-2, IL-6, NF-κB and TGF-β1 increased. As pro-inflammatory factors induced inflammation, anti-inflammatory factors also increased to protect the body from tissue damage. Conclusions: It can be concluded that excess iron can change the expression of main inflammatory factors in sheep liver, which will be an instructive significance to the development of medical prospect for sheep breeding and disease diagnosis.