The Influences Of Vitamin A On Intestinal Dendritic Cells And Mucosal Immunity Against Infection

Objective Vitamin A deficiency is still a serious problem that impairing the health of children in impoverished area.It has been known that VA plays a very important role in maintain of mucosal barrier,but the mechanisms of VA promote mucosal immunity are uncompleted clear.In this project,we studied effect of VA on the maturation and functions of mucosal dendritic cells(DC),and influence to mucosal immunity,to understand how VA enhances the immunity against infection in mucosa.Methods A rat model with VA deficiency(VAD)was set up,and intestinal infecions were induced by the oral inoculation of salmonella.By used of immuneohistochemical, RT-quantity PCR,ELISA,the affections of VA on the number and maturation of DC, antigenrecognition receptors and cytokines production,as well as the expressions of retinoic receptors(RARα,β,γ,RXRα,β,γ) in mucosa were detection.noicResults Compared with the VA normal rats,the numbers of DC in intestinal mucosa were increased in VAD rat,and when infection was complicated with VAD,both of the number and the maturation of DC were promoted.The expressions of TLR2 and TLR4 were elevated in mucosa,and higher expression of TLR2 was found in infected intestinal mucosa of VAD rats.IL-12 production,major from DC,was increased in intestinal mucosa of VAD rats,and more raised when infection was complicated.Productions of Th1 and Th2 cytokines from intestinal mucosa of VAD rats were reduced,and after infection these cytokines were still reduced.The expressions of RARα,RARγand RXRα,β,γwere down-regulated in intestinal mucosa of VAD rats,however,in infected intestinal mucosa these five receptors were up-regulated.Conclusions 1.The augment of the number and activation ofmucosal DC may play important roles in inflammatory reactions and impairment of mucosa in VAD rats.2.The markedly reduced production of Th1 and Th2 cytokines in intestinal mucosa was one of the important characters of the declined mucosal immunity in VAD rat.3.The regulation of VAD on the production of cytokines by local intestinal mucosa is likely to be an important mechanism of VAD affects intestinal mucosal immunity.4.The expressions of retinoic acid receptors in intestinal mucosa were positive correlated with VA states,and which was likely to involve into the regulation of VA on mucosal immunity.