Effects Of Astragalus Polysaccharides On Nitric Oxide Synthase In Mice With Chronic Stress

Astragalus polysaccharides,as an important bioactive substance is extracted from Astragalus membranaceus,is widely used as antioxidant stress medicine in clinical production of livestock and poultry.Under stress reaction,excessive nitric oxide can be combined with oxygen free radicals to produce peroxynitrite,which will destroy nucleic acid molecules,cause cell damage and lipid peroxidation,make cell death finally.Nitric oxide synthase,as the most important enzyme that catalyze arginine to produce nitric oxide,has an essential role for the regulation of the synthesis and balance of nitric oxide.Therefore,the effect of nitric oxide synthase in the antioxidant stress of Astragalus polysaccharides was preliminarily studied.In this study,a mouse model of chronic stress was constructed primarily.Astragalus polysaccharide was used in the treatment.The activity of total superoxide dismutase,the content of active oxygen and malondialdehyde in serum were examined.The antioxidant stress effect of Astragalus polysaccharide was verified.At the same time,Western-blot was used to examine the expression of nitric oxide synthase in main organs after Astragalus polysaccharides treatment.Immunofluorescence staining was used to assay the expression of NOS in stress injured organs.Chronic stress can cause a significant decrease in feed intake and body weight gain(P < 0.05),and liver organ index decreases significantly(P < 0.05).Astragalus polysaccharides can improve significantly the spleen organ index in normal mice(P < 0.05),and improve a reduction on food intake and weight gain of mice caused by chronic stress,and restore the liver organ index.Astragalus polysaccharides can restore the activity of serum total superoxide dismutase(P < 0.05)and decrease the content of active oxygen and malondialdehyde(P < 0.05)in the serum of chronic stress mice,and improve theanti-stress ability.Astragalus polysaccharides can reduce significantly the expression of iNOS in the heart and lung tissues of chronic stress mice(P < 0.05),reduce extremely significantly the expression of iNOS in the liver tissues,the expression of nNOS in the thymus tissue,and the expression of eNOS in the lung tissue of chronic stress mice(P < 0.01);improve the expression of iNOS in the thymus tissue and the expression of eNOS in the heart tissue of chronic stress mice significantly.Astragalus polysaccharides can significantly increase the expression of eNOS in liver tissues and the expression of iNOS in kidney tissues of normal mice(P < 0.05).In conclusion,Astragalus polysaccharides can prevent superoxide production,inhibit the production of hydroxyl radicals and keep the active oxygen content at a lower level.Inducible nitric oxide synthase may be more involved in the development and process of stress response.The anti-stress effect of Astragalus polysaccharides may keep the dynamic balance of nitric oxide in the body through regulating the stability of NOS.