The Effect of Gut Microbiota on the Progression of Intervertebral Disc Degeneration

OBJECTIVE: Intervertebral disc degeneration (IDD) is the main cause of back pain, and its treatment is a serious socio‐economic burden. The safety and treatment of fecal microbiota transplantation (FMT) has been established. However, the relationship between FMT and IDD still unclear. We aimed to explore whether FMT plays a role in IDD to provide a reference for the treatment of IDD. METHODS: An experimental model of IDD was established using 2‐month‐old male Sprague–Dawley rats. FMT was performed by intragastric gavage of IDD rats with a fecal bacterial solution. Rat serum, feces, and vertebral disc tissue were collected after surgery for 2 months. The levels of TNF‐α, IL‐1β, IL‐6, matrix metalloproteinase (MMP)‐3, MMP‐13, Collagen II, and aggrecan in the serum or vertebral disc tissue were measured by an enzyme‐linked immunosorbent assay, immunohistochemistry, quantitative real‐time polymerase chain reaction, or western blotting. We also examined the pathology of the vertebral disc tissue using hematoxylin and eosin (HE) and safranin O‐fast green staining. Finally, we examined the gut microbiota in rat feces using 16 S rRNA gene sequencing. RESULTS: We found that the expression of TNF‐α, IL‐1β, IL‐6, MMP‐3, MMP‐13, NLRP3 and Caspase‐1 increased in the IDD group rats. In contrast, Collagen II and aggrecan levels were downregulated. Additionally, vertebral disc tissue was severely damaged in the IDD group, with disordered cell arrangement and uneven safranin coloration. FMT reversed the effects of IDD modeling on these factors and alleviated cartilage tissue damage. In addition, FMT increased the gut microbiota diversity and microbial abundance in rats treated with IDD. CONCLUSION: Our findings suggest that FMT has a positive effect in maintaining cellular stability in the vertebral disc and alleviating histopathological damage. It affects the diversity and abundance of gut microbiota in rats with IDD. Therefore, FMT may serve as a promising target for amelioration of IDD.