[Maxing Shigan Decoction improves lung and colon tissue damage caused by influenza virus infection through JAK1/2-STAT1 signaling pathway].

Abstract

Based on Janus kinase 1/2-signal transducer and activator of transcription 1(JAK1/2-STAT1) signaling pathway, this study explored the immune mechanism of Maxing Shigan Decoction in alleviating the lung tissue and colon tissue damage in mice infected with influenza virus. The influenza virus infection was induced in mice by nasal drip of influenza virus. The normal group, model group, oseltamivir group, antiviral granule group, and Maxing Shigan Decoction group were designed. After intragastric administration of corresponding drugs or normal saline for 3 or 7 days, the body mass was measured, and lung index, spleen index, and thymus index were calculated. Based on hematoxylin-eosin(HE) staining, the pathological changes of lung tissue and colon tissue were observed. Enzyme-linked immunosorbent assay(ELISA) was used to detect serum levels of inflammatory factors interleukin-8(IL-8) and interferon-γ(IFN-γ), Western blot and real-time quantitative polymerase chain reaction(RT-qPCR) to determine the protein and mRNA levels of JAK1, JAK2, STAT1, interferon regulatory factor 9(IRF9), and IFN-γ in lung tissue and colon tissue. The results showed that after 3 and 7 days of administration, the body mass, spleen index, and thymus index were lower(P<0.05 or P<0.01), and the lung index was higher(P<0.01) in the model group than in the normal group. Moreover, the model group showed congestion, edema, and infiltration of a large number of lymphocytes and macrophages in the lung tissue, irregular structure of colon mucosa, ulceration and shedding of epithelial cells, and infiltration of a large number of inflammatory cells. The model group had higher levels of serum IFN-γ(P<0.01), higher protein and mRNA expression of JAK1, JAK2, STAT1, IRF9, IFN-γ in lung tissue(P<0.05 or P<0.01), higher level of JAK2 protein in colon tissue(P<0.01), and higher protein and mRNA levels of STAT1 and IRF9(P<0.05 or P<0.01) than the normal group. Compared with the model group, Maxing Shigan Decoction group had high body mass, spleen index, and thymus index(P<0.05 or P<0.01), low lung index(P<0.05 or P<0.01), and significant alleviation of pathological injury in lung and colon. Moreover, lower serum level of IFN-γ(P<0.05 or P<0.01), protein and mRNA levels of JAK1, JAK2, STAT1, IRF9, and IFN-γ in lung tissue(P<0.05 or P<0.01), JAK2 protein level in colon tissue(P<0.01), and protein and mRNA levels of STAT1 and IRF9(P<0.05 or P<0.01) were observed in the Maxing Shigan Decoction group than in the model group. After 3 days of administration, the level of serum IL-8 in the model group was significantly higher than that in the normal group(P<0.01), and the level in the Maxing Shigan Decoction group was significantly reduced(P<0.01). In conclusion, Maxing Shigan Decoction can significantly up-regulate body mass, spleen index, and thymus index, down-regulate lung index, reduce the levels of IL-8 and IFN-γ, and down-regulate protein and mRNA levels of JAK1, JAK2, STAT1, IRF9, and IFN-γ in lung tissue and protein and mRNA levels of JAK2, STAT1, and IRF9 in colon tissue, and alleviate pathological damage of lung tissue and colon tissue. The mechanism is the likelihood that it inhibits the activation of JAK1/2-STAT1 signaling pathway to alleviate the damage to lung and colon tissue damage.