Effects Of Apple Polyphenols On Immunocyte In Mice Treated With Restraint Stress

Object:This experiment, having restraint stress as a model, researched the changes of immunologic function, antioxidants and antioxidative enzymes and the variety of mitochondria function in mice. It would discuss the possible mechanism of Apple Polyphenols(AP) improving the status of immunologic function.Method:Kun Ming (KM) mice loaded with restraint stress were induced by fixed in the restraint cage. Animals were randomly divided into normal group, stress group, Apple Polyphenols (200 mg·kg-1) and Apple Polyphenols (400 mg·kg-1). The effect of Apple Polyphenols on immunologic function were observed by the changes in spleen index, the totall number of spleen cells and natural killer (NK) cell activity in mice sacrificed 3 days after restraint stress. Firstly, the malondialdehyde (MDA) contains and oxygen radical absorbance capacity (ORAC) levels in restraint mice spleen lymphocytes were detected to determine the intracellular oxidation and antioxidant status. At the same time, the activities of the key enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and antioxidant glutathione (GSH) in the free radical scavenging system were also determined. In addition, the mRNA expression of CuZnSOD, MnSOD and GSH-PX were also detected. Mitochondrion is the main generated place of free radical. Accordingly, we observed the mitochondrial respiratory chain complexⅠ,Ⅱ,ⅢandⅣthrough spectrophotometry instrument and examined the changes of the expression of Ndufs 1 and 8 mRNAs in spleen of mice through the method of RT-PCR to protect mitochondria function. By determination of these parameters in the free radical generation and the elimination system in the immunocyte, we explored the mechanisms about oxidative stress in stressed mice to reveal the immunomodulating effect of Apple Polyphenols.Result:An oral administration of Apple Polyphenols solution (200 and 400 mg·kg-1) for five consecutive days to restrained mice alleviated the stress-induced reduction of spleen index, the total number of spleen lymphocytes and spleen NK cell activity. Apple Polyphenols had shown to be decreasing MDA content and increasing ORAC in spleen lymphocytes. Apart from that, SOD activities in spleen lymphocytes were also increased after Apple Polyphenols administration. In addition, Apple Polyphenols increased the GSH in spleen lymphocytes. At last, Apple Polyphenols increased the activity of mitochondrial respiratory chain complex I and II, and also improved the expression of Ndufsland 8 mRNAs in spleen lymphocytes of mice. Conclusion:These findings suggested that Apple Polyphenols may have immunomodulating effect towards restraint stress by improving oxidative stress by scavenging free radical, keeping the balance of antioxidant and oxidant and protecting mitochondrial function.Novel Points:1 Immunomodulating effet of Apple Polyphenols was studied with these animal models for the first time.2 Restraint stress selectively affected the mitochondrial respiratory chain complexes in immunocyte.3 Apple Polyphenols alleviated the status of oxidative stress of immunocyte through improving mitochondrial function.