The Exploration Of Superoxide Dismutase From Bifidobacterium Infantis Inhibition Of Ovalbumin-induced Allergy

Food allergy is a major progressive public health disease over the past 20 years.Probiotics,as the balancer of intestinal microecology,and the regulator of intestinal mucosal immune response,the curative effect of which in immunotherapy of infant food allergy has been confirmed by some clinical research.A lot of studies had shown that strong oxidative stress were existed in food allergic patients,and probiotics could reduce the levels of oxidation,and enhance the expression and its activity of the antioxidant compounds,such as superoxide dismutase(SOD).In this thesis,bifidobacterium infants(BB)was chosed to assess the effect of BB on OVA-induced food allergy by establishing the OVA allergic mice model in vivo,meanwhileprobiotics and cell experiment in vitro.It was SOD mechanismthat BB scavenged the reactive oxygen species(ROS)in the OVA-induced allergic mice,regulated Th1/Th2 balance,and inhibited OVA-induced food allergy.The methods,results and conclusions were as follows.(1)BB affected OVA-induced allergy by the SODpathway.The OVA and cholera toxin(CT)were used to sensitize the mice,and before challenging,BB and sodium diethyl dithiocarbamate(DDC)wereas the inhibitor of SODto intervene the mice for establishing BB antioxidant OVA allergic mice model.The antigen specific immunotherapy treatment was thecontrol,and the allergenicity of the mice model was evaluated.The mice body weight changed not obviously being treated by BB,intervented by DDC and cured by antigen specific immunotherapy.the allergy symptoms scores of the mice became betterby intervention orantigen specific immunotherapy of BB,Pathological staining showed the intestinal mucosa was complete.There were fewer inflammatory cells and red blood cell invasion into tissue.The levels of the Th2 type related immunoglobulins(OVA-IgE,OVA-IgG1)and cytokines(IL-4,IL-5,IL-13)were decreased,while the Th1 type(OVA-IgG2 a and IFN-gamma)levels were increased,the Th1/Th2 allergic reaction were kept balance.BB could inhibit malondialdehyde(MDA)formation in the allergic mice intestinal,increase the SOD activity in the intestines of allergic mice.The way of DDC intervention had a negative effect on the inflammatory response of OVA allergic mice.In conclusion,BB could remove the ROS in the mice body,regulate Th1/Th2 balance,and inhibit the allergic inflammation in mice through the antioxidant way.(2)Effect of DDC on the activity of SOD.Through the anaerobic culturing BB amplification,BB were treated with different concentrations of DDC at different time,but the SOD activity in BB had no difference.The inhibitor type of SOD in BB still needs for further resarch.Treated with DDC,the activity of SOD in intestinal tissue homogenate protein decreased clearly.BB improved SOD activity in mice,inhibiting OVA induced mice allergic reactions.(3)Effect of BB on BMDC related cAMP/PKA and NF-?B inflammatory pathway.BMDC were treated with CT,OVA,the inhibitor H-89 of protein kinase A(PKA),the BB cracking protein(TPY),respectively.The content of MDA and the expression of inflammatory cytokines were then detected.The ROS generation in BMDC was decreased by BB cracking protein which had the SOD activity,the expressionof TIM4,MDA,cAMP,CD40,CD80,NF-?B in cells were distinctly inhibited,and the cAMP/PKA and NF-?B pathways were blocked,the BMDC sensitization reaction were relieved.