Shen-Ling-Bai-Zhu-San alleviates functional dyspepsia in rats and modulates the composition of the gut microbiota.

The pathogenesis of functional dyspepsia (FD) is multifactorial, and the gut microbiota may play a significant role. Shen-Ling-Bai-Zhu-San (SLBZS), a traditional Chinese herbal medicine, has been widely used in the treatment of FD, and appears to influence the gut microbiota. Therefore, we hypothesized that SLBZS would alleviate dyspeptic symptoms by adjusting the composition of the gut microbiota. To test this hypothesis, we aimed to evaluate the effects of SLBZS on FD and elucidate the mechanism that underlies the interactions between gut microbiota and FD during SLBZS treatment. We employed a rat model of FD induced by multiple forms of chronic mild stimulation. 16S rRNA gene sequencing and shotgun metagenomic sequencing were used to analyze the microbial communities in fecal samples from the rats. We found that the SLBZS improved dyspeptic symptoms in FD rats, such as weight loss, decreased intestinal motility, reduced absorptive capacity. Moreover, the SLBZS treatment reversed gut dysbiosis in FD. With SLBZS treatment, FD biomarkers including Prevotella, Mucispirillum and Akkermansia were decreased while SCFA-producing bacteria such as Adlercreutzia and Clostridium, and sulfate-reducing bacteria Desulfovibrio were enriched. Additionally, SLBZS normalized the dysregulated function of the microbiome, upregulating the pathways of energy metabolism and decreasing the oxidative stress as well as bacterial pathogenesis. Our study demonstrated that SLBZS could ameliorate dyspepsia, and amend the dysregulated composition and function of the gut microbial community, providing insight into the mechanism of SLBZS treatment for FD from the perspective of gut microbiota.