Effects of Qishen Dihuang Granules on Intestinal Microbiota in Experimental Autoimmune Myasthenia Gravis Model Rats

Objective Effects of Qishen Dihuang (QSDH) granules on intestinal flora of an experimental autoimmune myasthenia gravis (EAMG) model rat were investigated (CNBI:PRJNA910532). Methods Thirty-six female Lewis rats were assigned to Control, EAMG, QSDH-low-dose, QSDH-medium-dose, QSDH-high-dose, and Prednisone groups using the random number table method (6 rats/group). A rat EAMG model was established by injecting Ra97-116 peptide antigen. Each day for 30 days, gavages were administered to rats in the Chinese medicine group (QSDH granules in different concentrations), Prednisone group (prednisone), and Control and Model groups (0.5% CMC). After 30-day gavages, rat fecal samples were collected and the microbial community composition and diversity differences between intestinal microbiota of EAMG and QSDH granule-treated groups were analyzed using 16S amplicon sequencing to explore the effect underlying QSDH granules alleviation of EAMG. Results The clinical symptoms of rats in each treatment group improved significantly after the intervention treatment with QSDH granules. Comparison of the relative abundance of microorganisms in the gut flora of different groups with that of the EAMG group rats revealed: significantly lower phylum-level Bacteroidetes abundance and significantly greater Actinobacteria abundance in the QSDH-high-dose group and a significantly greater Firmicutes/Bacteroidetes ratio in the QSDH-medium-dose group; significantly increased family-level QSDH-high-dose group abundances of Lachnospiraceae and Trichospiraceae (Firmicutes), significantly increased QSDH-medium-dose group Lactobacillaceae abundance, and significantly increased QSDH-low-dose group Bacteroidaceae abundance; genuslevel, QSDH-high-dose group Prevotella and Coprococcus abundances were significantly increased and Turicibacter and Lactobacillus abundances were significantly decreased, while QSDH-medium-dose group Akkermansia and Lactobacillus abundances were significantly increased. Greater overall community richness, diversity, and genetic diversity were observed in QSDH granules-treated groups, but differences were insignificant (P >.05). The most significant inter-group genus-level community marker differences involved Prevotella, Ruminococcus, Coprococcus, and Turicibacter. Conclusion QSDH granules may regulate EAMG rat intestinal flora by decreasing relative abundances of Turicibacter and Clostridium and increasing relative abundances of Bifidobacterium, Lachnospiraceae, and Prevotella.