From accumulation to degeneration: Microplastics as emerging risk factors for intervertebral disc health

In recent years, the potential threat of microplastics (MPs) to human health has garnered increasing attention. The accumulation of MPs in human intervertebral disc (IVD) tissue (61 ± 44 particles/g) is significantly higher than that in bone (22 ± 15 particles/g) and cartilage (26 ± 17 particles/g), with larger average particle sizes-likely attributable to the unique composition and structure of the IVD. However, the mechanisms underlying MP deposition in the IVD and their impact on intervertebral disc degeneration (IVDD) remain largely understudied. Existing research conditions often differ from actual human exposure scenarios, detection methodologies lack standardized protocols, and effective strategies for MP removal and prevention remain limited.This review systematically elucidates the sources of MPs (e.g., degradation of daily-use plastics and medical waste disposal), their global distribution, and associated health risks, noting that humans ingest approximately 5 g of plastic per week. We further summarized the mechanisms by which they promote IVDD, such as through the induction of oxidative stress, and investigated their deleterious effects on key IVD-related cells, including chondrocytes, nucleus pulposus cells, and other relevant cell types. In addition, emerging detection and removal strategies, such as spectroscopy-microscopy integration and enzymatic degradation, are discussed. Overall, this study seeks to bridge current knowledge gaps by offering a comprehensive theoretical framework and practical insights for the prevention and mitigation of MP-induced IVDD.