Abstract:
Objective
To observe the effects of Ganlun Xiaodu micropill(GXM) and its volatile oil on the levels of IL-4, TNF-α, IFN-α/β and NS1 mRNA, RIG-Ⅰ mRNA and NF-κB protein in lung tissue of mice infected with influenza virus(IV)， in order to explore the molecular mechanism of the antiviral effect of GXM and its volatile oil.
Methods
A total of 36 SPF BALB/c mice， half female and half male， were randomly divided into 6 groups， with 6 rats in each group. They were normal group(A group)， model group(B group)， gavage group(C group)， intranasal group(D group)， combination group(E group) and oseltamivir group(F group). Except the normal group， the remained 5 groups were modeled with influenza virus FM1-6-E2. On the seventh day after the model， the mice were killed by picking up the eyeball and releasing blood. The lung tissue was detected by transmission electron microscope and the image was analyzed. The content of IL-4, TNF-α and IFN-α/β in serum was determined by ELISA，and the expression of NS1 and RIG-ⅠmRNA in lung tissue of mice was detected by qRT-PCR. Western blot method was used to determine the expression of NF-κB protein in lung tissues of mice.
Results
(1) The ultrastructure of lung tissue in the model mice after IV infection showed necrosis of type Ⅱ cells， destruction of alveolar structure， thickening and shedding of cilium in the alveoli， and pulmonary inflammation was formed. All the treatment groups were improved in the ultrastructural abnormal change of the alveolar type Ⅱ epithelial cells.(2) After IV infection in mice， the content of IL-4, TNF-α and IFN-α/β in serum and the expression of NS1 mRNA, RIG-Ⅰ mRNA and NF-κB protein in lung tissues were all higher than those in A group. The difference was significant between B group and A group; Compared with the B group， the serum levels of IFN-α/β in the serum of C，D，E and F groups increased significantly， while the content of IL-4， TNF-α and the expression of NS1 mRNA， RIG-Ⅰ mRNA and NF-κB protein were obviously down-regulated (P<0.05). There was significant difference in the anti-IV effect among different dosage forms of GXM treatment groups(P<0.05)，the effect being E group>C group>D group.
Conclusion
GXM has the function of anti-IV infection. It inhibits the pathological reaction of inflammation， enhances the content of immune factors and reduces the immune inflammatory injury induced by IV by inhibiting the activation of RIG-Ⅰ/NF-κB signaling pathway.

Key words: Influenza virus infection, Ganlu Xiaodu micropill, Volatile oil, RIG-Ⅰ, NF-κB, Mice