Effect Of Dhea On Immune Function In Mouse And Its Mechanism

Dehydroepiandrosterone(DHEA)is the most abundant steroidal substance in the blood circulation of the body,and it enters the blood circulation mainly in the form of sulphate ester.At present,the research on DHEA is mainly focused on its lipid metabolism,stress response,antioxidant capacity,etc.However,there are few reports systematically on the effects of DHEA on immune function in mice.Therefore,present study attempts to elucidate the effect of DHEA on immune function in mice through both in vitro and in vivo experiments.The research results will provide relevant theoretical basis for revealing the effect of DHEA on immune function and its mechanism,and also have certain guiding significance for improving livestock product quality and disease prevention and control.1 Effect of DHEA on the cell differention and immune factors secretion in mouses lymphocytesThis study aimed to investigate the effect of different concentrations of DHEA treatment on the proliferation,differentiation and the immune factors mRNA level in T lymphocytes and B lymphocytes,which will elucidate the mechanism of DHEA on immune immune function in vitro culture lymphocytes.The lymphocytes were isolated fom the spleen of mice,and the cells were stimulated with Concanavalin A(ConA)and lipopolysaccharide(LPS),respectively.T lymphocytes and B lymphocytes were obtained,and then treated with 0 μmol/L,5 p,mol/L,50 μmol/L,and 100 μmol/L DHEA for 24 h.After incubation,the cells proliferation was detected MTT assay;T lymphocyte typing was detected by Flow cytometry;the immune factors mRNA leves of IL-2,IL-4,IL-6,IL-10,IFN-α and TNF-β was anylsised by Real-time PCR;the activity of Na+K+-ATPase and Ca2+-ATPase in T lymphocytes and the intracellular Ca2+ concentration in B lymphocytes was detected by commercial kits.The results showed that no significant difference were observed on the proliferation of T lymphocytes treated with different of concentrations of DHEA,while 100 μmol/L DHEA significantly reduced the proliferation of B lymphocytes(P<0.05).50 μmol/L and 100 μmol/L DHEA treatment significantly improved the lymphocytes differention into T lymphocytes and exert immune function(P<0.01).Meanwhile,50 μmol/L and 100 μmol/L DHEA treatment significant enhanced the shift ofT-lymphocyte type toward to Thl cells.Treatment with of 50 μmol/L and 100 μmol/L DHEA significantly increased the Na+K+-ATPase activity T lymphocyte(P<0.01),but the Ca2+-ATPase activity significantly decreased in B lymphocyte(P<0.01).No significant changes were observed on the IL-10 and TNF-β mRNA level,while 50 μmol/L and 100μmol/L DHEA treatment significantly increased the IL-2 and IFN-α mRNA level and significantly decreased IL-4 and IL-6 mRNA level(P<0.01).These results indicated that DHEA treatment increased the immune fators expression level of secrestion by Thl cells and decreased the immune fators expression level of secrestion by Th2 cells.In addition,DHEA treatment improved the lymphocytes differention into T lymphocytes and enhanced the shift of T-lymphocyte type toward to Thl cells,and which might associated with the regulation of DHEA on the activity of Na+K+-ATPase and Ca2+-ATPase in T lymphocytes and the intracellular Ca2+ concentration in B lymphocytes.2 Effect of DHEA on phagocytic ability and factors secretion in mouse peritoneal macrophagesIn this study,we aimed to investigate the effects of DHEA treatment on the proliferation,phagocytosis and immune factors expression level in mouse peritoneal macrophages.The mouse peritoneal macrophages were treated with 0 μmol/L,5 μmol/L,50 μmol/L and 100 μmol/L DHEA for 24 hours.After incubation,the proliferation of peritoneal macrophages was detected by MTT assay;the phagocytic activity of macrophages was alysised by Neutrophil phagocytosis method;the amount of NO secreted by macrophages and the activity of iNO synthase were detected by the commercial kits;the mRNA levels of iNOS,IL-6,IL-8,IL-10 and TNF-β was detected by Real-time PCR.Results showed that 50μmol/L DHEA treatment significantly increased the proliferation of peritoneal macrophages(P<0.01).Compared with tcontrol group,5μmol/L and 50μmol/L DHEA treatment significantly increased the phagocytic ability of peritoneal macrophages(P<0.01).The NO secretion and iNOS activity were significantly increased in peritoneal macrophages treated with 5μmol/L or 50μmol/L DHEA(P<0.05).No significant differences were observed on the IL-6 and IL-8 mRNA level,but 50 μmol/L DHEA treatment significantly increased the iNOS,TNF-β and IL-10 mRNA levels in peritoneal macrophages(P<0.01).These results suggested that DHEA treatment increase the phagocytic ability of peritoneal macrophages,and enhanced the secretion of NO by increasing the iNOS activity in macrophages.Meanwhile,DHEA treatment improved the iNOS,TNF-β,IL-10 mRNA levels and then regulated the immune status.3 Effect of DHEA on the antioxidation and immune function in mice induced by peritoneal LPSIn this study,we investigated the effect of DHEA on the ant oxidation and immune function of mice stimulated with LPS.60 ICR mice were randomly divided into 5 groups.Each experimental group was fed with 0,5,50 and 100 μmol/L DHEA,500 μL per day for 1 week.Before the experiment end,all mice were stimulated with 100 μL of 2mg/mL LPS for 6 hours,and then collected the serum,spleen,liver and small intestine.Results showed that DHEA treatment significantly reduced ROS content of serum,intestinal,liver and spleen in mice(P<0.01).DHEA treatment significantly increased the total antioxidant capacity of serum,intestine,liver and spleen in mice(P<0.05).Compared with control group,no significant changes were observed on the SOD activity in liver,while 50 and 100μmol/L DHEA treatment significant the SOD activity of the serum,small intestine and spleen in mice(P<0.01).Compared with the control group,50 and 100μmol/L DHEA treatment significantly increase the serum IL-2 and IFN-a content(P<0.01),while serum IL-4 content was significantly decreased in mice treated with 50 and 100 μmol/L DHEA(P<0.05).DHEA treatment significantly increased the content of IFN-a in spleen,but the IL-10 content was significant decreased in the spleen of mice(P<0.01).50 and 100μmol/L DHEA treatment significantly increased the IL-2 in spleen(P<0.01),but significant decreased IL-4 content in the spleen(P<0.01).These results indicated that administration of DHEA can increase the antioxidant capacity and regulated the secretion of immune factors,and which regulated the immune function in mice stimulated with LPS.