Effect of feeding Chinese herb medicine ageratum-liquid on intestinal bacterial translocations induced by H9N2 AIV in mice

Abstract

Background As a low pathogenic influenza virus, avian influenza virus subtype H9N2 (H9N2 AIV) often induces high morbidity in association with secondary bacterial infections in chickens or mammals. To explore this phenomenon, the relationship between intestinal microflora changes and bacterial translocations was studied post H9N2 AIV challenge and post AIV infection plus Ageratum-liquid treatment. Methods Illumina sequencing, histological examination and Neongreen-tagged bacteria were used in this study to research the microbiota composition, intestinal barrier, and bacterial translocation in six weeks of BALB/c mice. Results H9N2 AIV infection caused intestinal dysbacteriosis and mucosal barrier damages. Notably, the villus length was significantly reduced ( p < 0.01) at 12 dpi and the crypt depth was significantly increased ( p < 0.01) at 5 dpi and 12 dpi with infection, resulting in the mucosal regular villus-length/crypt-depth (V/C) was significantly reduced ( p < 0.01) at 5 dpi and 12 dpi. Moreover, degeneration and dissolution of the mucosal epithelial cells, loose of the connective tissue and partial glandular atrophy were found in infection group, indicating that intestinal barrier function was weakened. Eventually, intestinal microbiota ( Staphylococcus , E. coli , etc.) overrun the intestinal barrier and migrated to liver and lung tissues of the mice at 5 and 12 dpi. Furthermore, the bacteria transferred in mesentery tissue sites from intestine at 36 h through tracking the Neongreen-tagged bacteria. Then the Neongreen-tagged bacteria were isolated from liver at 48 h post intragastrical administration. Simultaneously, Ageratum-liquid could inhibit the intestinal microbiota disorder post H9N2 AIV challenge via the respiratory tract. In addition, this study also illustrated that Ageratum-liquid could effectively prevent intestinal bacterial translocation post H9N2 AIV infection in mice. Conclusion In this study, we report the discovery that H9N2 AIV infection could damage the ileal mucosal barrier and induce the disturbance of the intestinal flora in BALB/c mice resulting in translocation of intestinal bacteria. In addition, this study indicated that Ageratum-liquid can effectively prevent bacterial translocation following H9N2 infection. These findings are of important theoretical and practical significance in prevention and control of H9N2 AIV infection. Electronic supplementary material The online version of this article (10.1186/s12985-019-1131-y) contains supplementary material, which is available to authorized users.

Effect of Baicalin on Bacterial Secondary Infection and Inflammation Caused by H9N2 AIV Infection in Chickens

“…Studies have shown that H9N2 AIV infection can promote the translocation of intestinal flora in mice [ 22 ], but the translocation of microflora in chicken intestine caused by H9N2 AIV infection is still unknown. Our study shows that H9N2 infection could promote translocation of the microflora from the intestinal metastasis to the mesentery, liver, and lungs in chickens at 5 dpi and 12 dpi.…”

Harringtonine Inhibits Zika Virus Infection through Multiple Mechanisms

“…To prevent the severe consequences of ZIKV infections and reduce ZIKV-induced neurological defects, an effective anti-ZIKV agent is required. Compounds isolated from natural plants have been widely evaluated in many antiviral studies [ 17 , 18 ]. Previous research on the natural Cephalotaxus alkaloids harringtonine, homoharringtonine, and cephalotaxine majorly showed antitumor effects, such as antileukemic activity [ 11 , 19 , 20 ].…”

Development and Effects of Influenza Antiviral Drugs

“…It has been reported that Gegen Qinlian decoction can downregulate the expression of some signaling pathway factors and the activity of NF-κB, inhibiting the expression of inflammatory factors and the cytokine storm, affecting the differentiation of CD4 + T cells and thereby increasing the antiviral immunity of the host [ 107 , 108 ]. The Gegen Qinlian decoction activates the host’s homeostatic inflammatory response, limits immunopathological damage, and improves clinical symptoms [ 107 , 108 ]. Similarly, Lianhua-qingwen is a traditional Chinese medicine prescription for the treatment of respiratory diseases that can relieve clinical symptoms such as fever, cough, sore throat, and fatigue and has a broad-spectrum inhibitory effect on influenza virus [ 109 ].…”