Two Isomers of Ginger Root Extracts Modify Composition and Function of Gut Microbiota in Rats Treated with Neuropathic Pain

Abstract

Abstract Objectives Emerging evidence has suggested that gut microbiota plays a key role during the development of chronic pain, such as neuropathic pain (NP). This study was to evaluate the effects of two ginger root extract isomers (gingerols and shogaols) on the composition and function of gut microbiota in animals with NP. Methods Sixteen male Sprague-Dawley rats were randomly assigned into 4 groups: sham group, spinal nerve ligation (SNL) group as the pain control group, SNL + gingerols-enriched ginger (GEG) extract group, and SNL + shogaols-enriched ginger (SEG) extract group. Animals in GEG and SEG groups were fed their respective diets on the day of SNL surgery for 30 days. At day 30, fecal samples were collected for microbiota composition and functional analyses. 16S rRNA gene sequencing was conducted from fecal samples and microbiome data analysis was performed with QIIME2 and PICRUSt2. Data were analyzed using non-parametric Kruskal–Wallis test to compare GEG and SEG with SNL group. Results Based on the results of alpha-diversity analyses, neither GEG nor SEG treatment affected the evenness of microbiome. Gingerols or shogaols supplementation into the diet reduced the richness of the gut microbiome, compared to the SNL group. Relative to the SNL group, GEG group had an increase in the relative abundance of the genus Faecalitalea, while SEG group had an increase in the relative abundance of the genus Aerococcus and species Bacteroides massiliensis. In comparison to SNL group, both GEG and SEG groups showed a decrease in the relative abundance of the family Muribaculaceae and the genus Rikenellaceae RC9 gut group. Functional profiling results revealed that relative to the SNL group, both GEG and SEG supplementation increased the proportion of biosynthetic pathways related to energy metabolism (i.e., pentose phosphate pathway and sugar degradation) and peptidoglycan biosynthesis. Furthermore, GEG and SEG differentially modified amino acid-related metabolic pathways, i.e., tyrosine degradation, tryptophan biosynthesis, arginine, and ornithine biosynthesis. Conclusions GEG and SEG exhibited differential effects on the microbiome composition and function, suggesting a prebiotic potential for dietary ginger root intake in the management of NP. Funding Sources Texas Tech University Health Sciences Center.