Establishing a high iron model and observing indexes related to iron metabolism in mice

Hang ZHU; Haiji LUO; Hong DENG; Lei LEI; Shouhua ZHANG

ABSTRACT

BACKGROUND:

In recent years, epidemiological studies have found that the saturation of transferring or the increased level of serum ferritin are associated with the attacks of cancer, coronary heart disease, diabetes mellitus, Parkinson disease, liver disease and the diseases of immune system. Therefore, it is suggested that the intake of excessive iron may cause adverse influence on the healthy of human body.

OBJECTIVE:

To establish high-iron model in mice by using full-rate diet pellets by adding regular quantitative intraperitoneal injection of iron dextran, and observe the iron levels in vivo and the changes of organ coefficients.

DESIGN:

A comparative observation.

SETTING:

Department of Nutrition and Food Hygiene, School of Public Health and Tropic Medicine, Southern Medical University.MATERIALS The experiment was carried out in the laboratory of the Department of Nutrition and Food Hygiene, School of Public Health and Tropic Medicine, Southern Medical University in May 2006. Forty Kunming mice of SPF grade, 20 males and 20 females, weighing 18-22 g, were provided by the Animal Experimental Center of Southern Medical University. The mice were randomly divided into control group (n =10) and high-iron model group (n =30) by introperitoneal injection of saline and iron dextran respectively, and the latter group was subdivided into low, middle and high-dosage groups (6.25, 12.5 and 25 g/L) respectively, 10 mice in each group. Full-rate diet pellets (iron content was 370 mg/kg)were purchased from the Animal Experimental Center of Southern Medical University. Iron dextran reagent (norm 2 mL containing 50 mg iron) was the product of Zhejiang Ruian Pharmaceutical Factory (certification number H33021758).The kits of superoxide dismutase (SOD) and maldondialdehyde (MDA) were provided by the Nanjing Jiancheng Bioengineering Institute.

METHODS:

Mice in each group were raised in plastic stainless steel cages respectively at (23±3) ℃, and they were free to the access of food and deionized water. Mice in the low, middle and high-dosage group were treated with intraperitoneal injection of iron dextran once every other day, 0.8 mL for each time, whereas iron dextran was replaced by saline in the control group, all the mice were treated for 6 weeks, and their nutritionol conditions were observed. All the mice were killed at the end of the 6th week. The iron contents in organs of heart, liver, spleen, lung and kidney, and serum were determined with atomic absorption spectrophotometer and automatic biochemical analyzer respectively; Pathohistological examination of organs were performed; The organ coefficients of liver and spleen were calculated; MDA content and SOD activity in serum were determined.MAIN OUTCOME

MEASURES:

General conditions of mice in each group; Iron contents in organs and iron concentration in serum; Organ coefficients of liver and spleen; MDA content and SOD activity in serum; Pathological changes.

RESULTS:

In the high-iron model group, the body figures of the mice were changed, body masses were obviously decreased. The iron contents in organs and serum of mice in the high-iron model group were all obviously increased as compared with those in the control group (t =5.841, P ＜ 0.01), the organ coefficients of liver and spleen were also markedly increased (t =5.841, P ＜ 0.01), which were all in a dosage-dependent manner. The MDA content in serum was obviously increased (t =5.841, P ＜ 0.01) whereas the SOD activity was obviously decreased (t =12.924, P ＜ 0.01) as compared with those in the control group. The pathohistological examination under light microscope showed that there were pathological damages of different degree occurred in the tissue and cells and cell degeneration was observed,which affected the normal physiological function of cells.

CONCLUSION:

High-iron mice models can be successfully established by the intraperitoneal injection of iron dextran.The storage of excessive iron in vivo will result in the organic damages.