Protective effect of polysaccharides fractions from Sijunzi decoction in reserpine-induced spleen deficiency rats

This work focuses on exploring the active polysaccharide fraction from Sijunzi decoction (SJZD), which is a classical herbal prescription in traditional Chinese medicine (TCM). Three polysaccharide fractions (S-1, S-2, S-3) were obtained from SJZD, the effects of which on the immune system (organic, cellular and molecular levels) and intestinal microbiota, as well as their metabolites (short chain fatty acids, SCFA) were investigated in reserpine-induced Wistar rat models. The results revealed that the spleen index, IL-2 and IFN-gamma levels of S-3 group were significantly decreased compared to the model group, and the CD4+/CD8+ ratio displayed a significant increase in the S-3 group, indicating the immune enhancing effect of polysaccharide fraction S-3. Moreover, the disturbance of gut microbiota induced by reserpine was restored after administration of polysaccharide fraction S-3, indicated as the Shannon's diversity index and similarity coefficient index both increased significantly in S-3 group. In SCFA analysis, the content of acetic acid, propionic acid and butyric acid in faeces of S-3 group rats was also significantly increased after treated with S-3. All the results consistently indicated that polysaccharide fraction S-3 from SJZD could mitigate effect in the reserpine-induced rats and potentially treat spleen deficiency. The comprehensive screening strategy established in this study may provide a new idea to achieve further understanding of TCM.