Effects Of Aerobic Exercise On Iron Metabolism In Adult Mice

Iron is a trace element essential to the human body.With the increase of age,iron content in the body increases and iron deposition occurs.Excessive iron can cause cell damage and increase the risk of some chronic diseases.The liver is the main organ responsible for iron storage and metabolism in the body and many diseases have significant hepatic iron accumulation.When there is excessive iron in the liver,it induces apoptosis of liver cells,which promotes liver fibrosis and liver cancer.Aerobic exercise can increase the consumption of iron in the body and reduce the iron content in the body.In the process of gradual accumulation of liver iron content in middle-aged and old mice,whether aerobic exercise can promote liver iron release by promoting the release of liver iron from the body,and then the redistribution of liver iron and other tissue iron needs further study.In this study,natural aging mice were used as experimental animal models.Through aerobic exercise intervention,the preventive effect of aerobic exercise on iron deposition in liver of adult mice was explored,and experimental basis was provided for the prevention of iron overload-related chronic diseases.Contents and Methods:Part I: The iron status of mice at different ages.Sixteen C57BL/6 male mice aged 13 months were weighed at 30 g ± 2g.They were randomly divided into 13-month-old group(13 months,13M)and 18-month-old group(18 months,18M),8 in each group.The 13 M group was adapted for feeding,and the 18 M group was fed until 18 months of age.Serum ferritin levels in mice were measured by ELISA;serum iron levels,serum total iron binding capacity,and iron contents in liver,heart,spleen,kidney,gastrocnemius muscle,and bone marrow were determined by spectrophotometry;The concentration of related proteins,such as FPN1,DMT1 and CP in liver were detected by Western Blot;The expression of Hepcidin mRNA in mouse liver was measured by Real Time-PCR.Part II: Effect of exercise on iron status in mice.Sixteen C57BL/6 male mice aged 13 months were randomly divided into a control group(C)and an exercise group(E),8 in each group.The control group was fed quietly and the exercise group was given an aerobic exercise intervention.The exercise intervention used a mouse treadmill,which was adapted for 3 days of exercise,22 weeks of formal exercise,6 days of exercise per week,and 1 day of rest.The exercise time is 45min/d,the speed is 10m/min,the exercise gradient is 0,every 2 weeks increase 1m/min up to 15m/min,then every two weeks decrease 1m/min until 10m/min.After 22 weeks of exercise intervention,we took the body tissue from mice.Determination of serum iron,total iron binding capacity,serum ferritin content,and tissue iron content in liver,heart,spleen,kidney,gastrocnemius muscle,and bone marrow;The expression of Hepcidin mRNA,FPN1,DMT1 and CP in liver was detected.The experimental data obtained were processed and analyzed by SPSS20.0 statistical software.All the values were expressed as “mean ± standard deviation”.Independent sample t-test was used for comparison between groups.P<0.05 indicated that the difference was significant,P<0.01 The difference is highly significant.Results:(1)Iron levels in mice of different ages: Serum iron content,serum total iron binding capacity,transferrin saturation,and serum ferritin levels in mice aged 18 months were significantly lower than those in the 13-month old group(P<0.01).The tissue iron level was higher than the 13-month-old group.Compared with the 13-month-old group,the iron content in the liver and spleen of the main iron-storing organs of the 18-month-old group was significantly increased(P<0.05);the iron levels in the heart,kidney,and bone marrow were significantly increased(P <0.01);while the iron content of gastrocnemius muscle has a significant decrease trend(P <0.05).(2)Expression of liver-related proteins in mice of different age groups: The expression of FPN1 protein and CP protein in livers of 18-month-old mice was decreased(P<0.05,P<0.01).Compared with the 13-month-old group,the expression of DMT1(+IRE)protein was significantly decreased in the 18-month-old group(P<0.01),and the expression of DMT1(-IRE)protein was decreased(P<0.05).The expression of Hepcidin mRNA in liver of 18-month-old mice was significantly higher than that in 13-month-old mice(P<0.01).(3)Effects of exercise on iron levels in mice: Compared with the control group,serum iron and serum total iron binding capacity of the exercise group increased(P<0.01),and transferrin saturation and serum ferritin content also increased(P<0.05).After the intervention of aerobic exercise,iron contents in liver,spleen,and heart of the main iron-storing organs of the exercise group decreased(P<0.01);iron levels in the kidneys and bone marrow decreased(P<0.05);iron contents in the gastrocnemius muscles of the exercise group presented a tendency of increasing and there was a very significant difference compared with the control group(P<0.01).(4)Effects of exercise on expression of hepatic related proteins in mice: After 5 months of aerobic exercise intervention,liver FPN1 protein,DMT1(+IRE)and DMT1(-IRE)protein expression were significantly higher in the exercise group than in the control group(P<0.01).In the exercise group,the expression of CP protein also increased(P<0.05).The expression of hepcidin mRNA in the liver of mice decreased after aerobic exercise(P<0.05).Conclusion:(1)With the increase of age,the liver iron content of aged mice increased and iron deposition appeared.Liver FPN1,CP and DMT1 protein expression decreased,and Hepcidin mRNA expression was increased.(2)Aerobic exercise can promote the release of iron in the liver and relieve the liver iron deposition in elderly mice.Aerobic exercise reduced the expression of Hepcidin mRNA in the liver of elderly mice,and increased the expression of FPN1,CP and DMT1 in the liver.