From the Department of Medical Elementology and Toxicology, Hamdard University, New Delhi-
Abstract: (5180 Views)
Iron overload is known to occur in the West European and American
population due to the consumption of iron-rich diets. On the other hand, genetic
disorders leading to iron overload are also known. Iron overload leads to increased
peroxidation and disruptive disintegration of lipid-rich membranes, and predisposes
humans for an enhanced risk of cancer induction. In experimental animals iron
overload enhances intestinal, colonic, hepatic, pulmonary and mammary
carcinogenesis. In this study, we have shown that iron overload is a mild tumor
promotor in mouse skin. Female albino Swiss mice were iron overloaded and their
backs were shaved. Tumors were initiated using a complete tumorigenesis
protocol by applying 200lig 7, 12-dimethylbenz (a) anthracene (DMBA)/mouse in
multiple doses of 40llg DMBA/day for 5 consecutive days. The appearance of the
first tumor (latency period), percent of tumor incidence and number of tumors/
mouse were recorded. When compared to the positive control group, the iron
overloaded mice showed an increased incidence of tumors. In iron overloaded
animals, the tumors appeared about four weeks earlier. The number of tumors per
mouse were significantly higher in the iron overloaded group. Biochemical studies
performed in the present study include the determination of the activity of lipid
peroxidation, catalase and xanthine oxidase measurement in mice skin tissue. We
observed an iron-mediated induction in lipid peroxidation (LPO) and xanthine
oxidase (XOD) and diminished catalase (CAT) activity in skin tissues of mice
overloaded with iron as compared to the normal unloaded control group. Based on
these studies we propose that iron increases tumor promotion potentials significantly.
An induction in LPO in the iron overloaded group suggests that oxidative stress
may be responsible for such an observed augmentation of cutaneous carcinogenesis
in mice. Our data indicate that iron overload exerts tumor promoting potential in
mouse skin, and that oxidative stress generated by iron overload is responsible for
the augmentation of cutaneous tumorigenesis