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Qi-Wei-Bai-Zhu powder improves inflammatory response via the myd88 pathway in neonatal mice infected with human rotavirus

Canrong Wu, Shengnan Zuo, Biqiang Sun, Chaolong Chen, Zhou Yin, Biyuan Liu, Kejia Shen, Xihong Zhou

Qi-Wei-Bai-Zhu Power (QWBZP), as one of the classic herbal prescription, has been proved to decrease diarrhea incidence, reduce mortality and regulate cytokines secretion in both human and rodents infected with Rotavirus (RV). We conducted the present study to elucidate the specific mechanism how QWBZP exerts its beneficial effects on HRV infection in neonatal mice. Cytokine contents and expression of proteins in Toll-Like Receptor 3 (TLR3) pathway were determined in HRV and QWBZP treated neonatal mice and CD 8 T cells. The results showed that QWBZP decreased diarrhea incidence and fecal virus shedding in HRV-infected mice. Moreover, QWBZP decreased interleukin (IL)-1β, Tumor Necrosis Factor-α (TNF-α), interferon (IFN)-α and IFN-β contents and increased IL-10 content in both serum and intestine in HRV-infected mice. QWBZP, as well as myeloid differentiation factor 88 (MyD88) inhibitor peptide, downregulated MyD88-NFκB pathway and improved cytokines secretion, however, they did not affect TLR3 expression in HRV-treated CD 8 T cells. In addition, neither QWBZP nor MyD88 inhibitor peptide exerted any effects on NFκB expression and cytokines secretion in poly (I: C)-treated CD8 T cells. In conclusion, our results indicated that HRV activated TLR3 pathway and its downstream target NFκB dependent on MyD88, while QWBZP selectively inhibited MyD88 which further inactivated NFκB pathway and subsequently improved the production of cytokines, without affecting TLR3.