It is known that many tumors induce iron and zinc deficiency in the organism. We studied the content of these metals, as well as the specific activity of two antioxidant metal-dependent enzymes – catalase and superoxide dismutase of three distal organs (thymus, liver and spleen) in animals bearing transplantable hepatoma 22a. These alterations were compared to weight changes of organs. On day 21 of tumor growth, as compared to control group, nonheme iron content in all three organs was decreased, and zinc content – only in the thymus. The specific activities of catalase and superoxide dismutase were both increased in the thymus, while in the liver activity of superoxide dismutase decreased. At the same time point thymic involution and splenomegaly were developed. In order to normalize metal content mice bearing hepatoma 22a were supplemented with 22 mkg of zinc sulphate per ml of drinking water during 3 weeks. Zinc sulphate supplementation partly compensated zinc deficiency in the thymus, increased zinc content in the liver and restored iron content in three organs. It also normalized superoxide dismutase activity in the liver and had no influence on enzymes in other organs. Zinc supplementation did not influence the weight of spleen and liver, but prevented the development of thymic involution. Moreover, metal deficiency in the thymus was restored while the activity of antioxidant enzymes remained unchanged. Based on this we can conclude that thymus involution in hepatoma 22a mice was associated with iron and zinc deficiency in this organ and was not linked with antioxidant enzyme activity, while splenomegaly had no relation to both types of parameters in the spleen. Thus, zinc sulphate positively influences metabolism of two vital trace elements – zinc and iron in animals bearing hepatoma 22a, what contributes to maintaining of the central immune organ – the thymus, and along with this it improves antioxidant system of the liver.
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