The treatment effect of murine Interleukin-12 in mouse asthma

Objective To observe the effects of Intranasal Immunization with miurine interleukin-12 (mIL-12) on the antigen induced Airway inflammation and T helper cell subsets in mouse asthma models. Methods Construct pSEC:mIL-12 vector and transform to NZ9000,mIL-12 was expressed in lactis by the induction with Nisin.After centrifugation,Concentration of bacterial supernatants was Intranasal administration with murine.Fifty mice were divided into 5 groups by digits table:(A) control group;(B) phosphate-buffered saline (PBS)group;(C) wild Lactococcus lactis group;(D) Recombinant IL-12 group; (E) Recombinant Lactococcus lactis group.Except A group,Mice of the other groups were peritoneally sensitized with ovalbum (OVA,100μg/mouse) in three times on 1,7 and 14 days,and challenged by inhalation of 2% OVA one times a day from day 20 to 26,on day 1,2,3,14,19,20 and 21,B,C,E groups was administrated by nasal drip with 10μl of PBS,wild laetis(a total of 5 × 10~8CFU)and Recombinant lactis (a total of 5 × 10~8CFU).On day 20,21 and 22 D group was administrated by nasal drip with 3ng of Recombinant IL-12.All group were sacrificed on day 28.The concentration of Interleukin-4 (IL-4) and interferon-γ(IFN-γ) in bronchoalveolar lavage fluid (BALF) was measured by enzyme-linked immunosorbant assay(ELISA).A count of eosinophils (EOS) were quantified by cell count and histopathological analysis. Results Protein level of IL-12 can be secreted by Lactococcus lactis in higher expression.The concentration of EOS of groups(A-E) in BALF was 0.51±0.23 × 10~4 cell/ml,21.32±5.71 × 10~4 cell./ml,22.84±6.16 × 10~4 cell/ml,2.15±0.63 × 10~4 cell/ml,2.62±0.73 × 10~4 cell/ml,respectively;the concentration of IL-4 was 68.43±9.08 pg/ml,332.13±61.36 pg/ml,324.65±57.27 pg/ml,121.25±35.55 pg/ml,114.22±15.70 pg/ml,respectively;the concentration of IFN-γ was 110.28±12.19 pg/ml,56.25±12.08 pg/ml,70.36± 8.27 pg/ml,166.11±57.12 pg/ml,171.75±60.90 pg/ml,respectively.There were significant diffirence in the concentration of EOS,IL-4,IFN-γ of groups B and C compared with group A,respectively(P0.01). There were statistical diffirence in the concentration of EOS,IL-4,IFN-γof groups D and E compared with group B and C,respectively (P0.01).There were no significant change in EOS,IL-4,IFN-γ between group D and E.The histopathological results shows that in the intranasal administration with recombinant IL-12 groups,the infiltration of inflammatory cell was markedly reduced and the damage of airway epithelium was alleviated.Conclusion Intranasal administration recombinant IL-12 can reduce the side effect by system used.The molecular mechanisms by intranasal administration with recombinant IL-12 on murine asthma model play a indivect role by the downregulation of IL-4 expression and the upregulation of IFN-γ expression in the lung.