Baicalin Is Curative Against Rotavirus Damp Heat Diarrhea by Tuning Colonic Mucosal Barrier and Lung Immune Function

Previous studies have indicated that rotavirus (RV) is a causative factor for diarrhea and gastroenteritis in pediatric and neonatal settings. Baicalin has many functions, including antibacterial, antiinflammatory, and antihypertensive activities. However, the immunological mechanism of RV-induced diarrhea with heat-dampness syndrome (RV-DH) remains unclear.

The aim of this study is to explore the role of baicalin in RV-DH diarrhea and its underlying mechanism.

A mouse model of pediatric RV-DH diarrhea was established and treated with baicalin. The concentrations of cytokines were detected by enzyme-linked immunosorbent assay. Messenger RNA (mRNA) expression levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR), while protein expression levels were determined by Western blotting and immunohistochemistry. Flow cytometry was used to detect the frequency of lymphocytes.

The concentrations of interleukin-1β (IL-1β), IL-2, IL-6, IL-8, RVvb, and secretory immunoglobulin A (SIgA) in bronchoalveolar lavage fluid (BALF) and colonic mucosa were significantly increased in the RV-DH group. Decreased expression of occludin, claudin-1, and zonula occludens-1 (ZO-1) indicated loss of tight junction function and disturbances in intestinal mucosal permeability in the RV-DH group. Flow cytometry analysis showed a high rate of CD8⁺ lymphocytes and low amount of CD4⁺ lymphocytes in the RV-DH group. Treatment of RV-DH mice with baicalin significantly reduced the duration of diarrhea and ameliorated the symptoms and pathological and immunological changes. Furthermore, baicalin inhibited STAT1 and activated STAT3 signaling pathways.

These findings indicate the curative and immunoregulatory properties of baicalin and have direct practical and clinical relevance for the treatment of RV-DH enteritis in humans.