Effects Of Vitamin A On Immune Function And Reproductive Performance Of Pregnant Mice Infected Pseudorabies Virus

This study was conducted to investigate effects of vitamin A on immunity and reproductive performance on 9^th pregnancy of mice infected Pseudorabies Virus.The mice model with vitamin A deficiency was established,160 mice weighted 36.65±7.35(g) were assigned to 8 treatments according to an incomplete paired design.Mice in the three control groups were injected with PBS and supplied with vitamin A at 0,4000 and 10000 IU/kg, respectively;mice in the five experimental groups were infected Pseudorabies Virus and supplied with Vitamin A at 0,4000,10000,25000 and 50000 IU/kg,respectively.Female mice were injected Pseudorabies Virus or PBS on 0^th pregnancy and mice were killed on 9^th pregnancy to collect serum,brain,liver,spleen,uterus and embryos.Hepatic retinol concentration was determinted by HPLC,Ordinary PCR was used to determine PRV infection in brain,calculation spleen index,Immunity Transmission Turbidimetry was applied to determine maternal immunoglobulins(IgG,IgA,IgM) concentration in serum,ELISA was applied to determin cytokine(IL-1β,IFN-γ,IL-4,IL-10) concentration in serum,and real time-quantitative RT-PCR was applied to determine the expression of genes(TLR3,TLR7,TLR9) in uterus and embryos.The results were as follows:1,Hepatic retinol concentration increased with vitamin A level and was lower in the challenged than in the PBS group.Among challenged groups,hepatic retinol concentration in the 50000 IU/kg group was significantly higher than other vitamin A groups(P＜0.05), and between 4000 IU/kg groups,it was significantly lower in the challenged than in the PBS group(P＜0.05).2,Among challenged groups,spleen index was significantly lower in the 0 IU/kg than in other groups(P＜0.05),among PBS groups,it was significantly lower in the 0 and 4000 IU/kg group than in the 10000 IU/kg group(P＜0.05).and between 4000 IU/kg groups,it was significantly higher in the challenged than in the PBS group(P＜0.05). 3,Among challenged groups,IgA and IgM concentration in the 50000 IU/Kg group was significantly higher than in the 0IU/Kg group(P＜0.05).IgG concentration increased with vitamin A level except 0 IU/Kg group,and it was significantly lower in the 0 IU/Kg group than in the 10000 IU/kg,25000 IU/Kg and 50000 IU/Kg group(P＜0.05).Among PBS groups,IgA,IgM,IgG concentration increased with vitamin A level increased.Compared with PBS groups,IgG concentration increased and IgA,IgM concentration decreased in challenged groups at the same vitamin A level.4,With vitamin A level increased,IL-1β,IFN-γconcentration tended to decrease and IL-4,IL-10 concectration tended to increase.Among challenged groups,IL-1βconcentration in the 25000 IU/Kg group was significantly lower than in other vitamin A groups(P＜0.05). IFN-γconcentration in the 10000 IU/Kg group,25000 IU/Kg group and 50000 IU/Kg group were significantly lower than in the 0 IU/Kg and 4000 IU/Kg group(P＜0.05).IL-4 concentration in the 25000 IU/Kg group was significantly higher than in other vitamin A groups(P＜0.05).IL-10 concentration in the 25000 IU/Kg group was significantly higher than in the 0 IU/Kg,4000 IU/Kg and 10000 IU/Kg group(P＜0.05),and there were no significant differences between 25000IU/Kg group and 50000 IU/Kg group(P＞0.05). Among PBS groups,IL-1β,IFN-γconcentration in the 10000 IU/Kg group was significantly lower than in the 0 IU/Kg group(P＜0.05).IL-4 and IL-10 concentration increased with vitamin A level increased,and IL-4 concentration in the 10000 IU/Kg group was significantly higher than in the 0 IU/Kg group(P＜0.05).Compared with PBS groups, IL-1β,IFN-γconcentration increased and IL-4,IL-10 concentration decreased in challenged groups at the same vitamin A level.5,With vitamin A level increased,expression of TLR3/TLR7/TLR9 decreased.Among challenged groups,they were significantly lower in the 25000 IU/Kg and 50000 IU/Kg group than in the 0 IU/Kg and 4000 IU/Kg group(P＜0.05).Among PBS groups,expression of TLR3,TLR9 in uterus and embryos and TLR7 in embryos in the 10000 IU/Kg group were significantly lower than in the 0 IU/Kg group(P＜0.05).Expression of TLR3,TLR7,TLR9 was higher in challenged group than in the PBS group at the same vitamin A level.6,Morality and abortion rate increased postchallenged,and tended to decrease with vitamin A level increased(P＞0.05). 7,Among challenged groups,live embryos and live litter size in the 25000 IU/Kg group were significantly higher than in the 0 IU/Kg group(P＜0.05).Regression analysis revealed that there was a quadratic increase in live embryos on 9^th pregnancy,with the highest values observed at 34265 IU/kg(8.5 times that of mice with normal live embryos).Among PBS group,live embryos on 9^th pregnancy and live litter size increased with vitamin A level increased.Live embryos and live litter size decaresed when infected PRV,and between 4000 IU/kg groups,it was significantly lower in the challenged than in the PBS group(P＜0.05).Conclusion:1,When vitamin A level was in marginal deficiency,Pseudorabies Virus infection resulted in increased abortion rate and mortality and decreased live embryos and live litter size;However,abortion rate and mortality decreased and live embryos and live litter size increased when supplied vitamin A,and vitamin A requirement of female mice with highest live embryos on 9^th pregnancy was 8.5 times that of mice with normal live embryos.2,When vitamin A level was in marginal deficiency,Pseudorabies Virus infection resulted in increased expression of TLR3,TLR7,TLR9,then aggvarated expression of Th1 inflammatory factors,then affected Th1/Th2 immune balance,which was harmful to reproductive performance;However,expression of TLR3,TLR7,TLR9 decreased and level of Th2 antiinflammatory factor increased when supplied vitamin A,then Th1/Th2 immune balance improved which provided protective effect to embryonic development.3,Spplied vitamin A to pregnant mice infected PRV can increase serum immunoglobulin concentration,increase humoral immunity and improve embryos development.