Effects Of Administration Of Atriplex Hortensis Polysaccharide On SMAD4and Hepcidin Of Rats During Prolonged Strenuous Exercise

SMAD4is one member in transforming growth factor-beta superfamily members of signal transduction, It primarily responsible for the TGF-beta superfamily signal from the cell to the nucleus along with the other protein of SMADs family members. Recently, study found that SMAD4is a key upstream signal factor in which mediated hepcidin expression through the BMP-SMADs pathways. Hepcidin is one of important down-regulation factors in iron homeostasis. The expression of hepcidin was up-regulationed and caused iron deficiency during prolonged strenuous exercise. The present study investigated the effects of administration of atriplex hortensis polysaccharide(AHP) on SMAD4and hepcidin for illuminating the molecular mechanism of improve iron deficiency.Methods:24male wistar rats were randomly divided into three groups:control group(CG), exercise group(EG), exercise plus AHP, EP). The groups EG and EP underwent treadmill training at25m/min and0%grade, started from1minute and increased2minutes every day for5weeks,6days per week, once a day in the first two weeks and twice a day in the last three weeks.2ml AHP leaves extract(with the dosage of100mg/kg BW) was applied to the group EP once a day, and the same volume of normal saline to groups EG and CG. All rats were sampled after5-week running. Serum iron, serum unsaturated iron binding capacity, total iron binding capacity of liver were observed by ultraviolet spectrophotometry, and the expressions of EPO,SAMD4and hepcidin mRNAby RT-PCR.Results:(1) The numbers of RBC, Hb, Hct in EG after5weeks were significantly decreased, The numbers of WBC significantly increased compared with CG (P<0.01), EP were no significantly changes compared with CG; The numbers of RBC, Hb, Hct in EP increased (P<0.05), the numbers of WBC significantly decreased compared with EG (P<0.01).(2) Serum iron, unsaturated iron binding force and serum total iron binding force in EG significantly decreased compared with CG(P<0.01), Serum iron, unsaturated iron binding force and serum total iron binding force in EP significantly decreased compared with CG and significantly higher than EG(P<0.05).(3) The expression of EPO in EG significantly decreased compared with CG(P<0.05), The expression of EPO in EP significantly increased compared with CG and EG(P<0.01).(4) The expression of SMAD4and hepcidin mRNA in EG significantly increased compared with CG (P<0.01), whereas SAMD4and hepcidin mRNA significantly decreased compared with CG and EG in EP.(P<0.05)(P<0.01)Conclusion:(1) The prolonged strenuous exercise not only could cut down the number of RBC and Hb,but also triggered the body’s inflammatory response and effect the body’s oxygen carrying capacity. Suppled Atriplex Hortensis Polysaccharide could promote erythropoiesis, alleviate the body’s hypoxia phenomena and also could reduce the inflammation caused by the prolonged strenuous exercise.(2) The expression of hepcidin mRNA was significantly increased is the main factor which caused serum iron levels decreased during prolonged strenuous exercise in rats. At the same time, The prolonged strenuous exercise could cause the body iron consumption, It was also one of factors caused serum iron levels in rats.(3) Suppled Atriplex Hortensis Polysaccharide could inhibit the expression of SMAD4, up-regulation hepcidin levels, improve iron deficiency during prolonged strenuous exercise in rats.(4)AHP could stimulate the EPO secretion of rats, suppress the expression of SMAD4and hepcidin mRNA, and thus improve iron deficiency during prolonged strenuous exercise in rats.