Objective: To investigate whether Salvianolic acid A (SAA) can restore cartilage endplate cell degeneration of intervertebral discs and to identify the mechanism via regulation of micro-RNA.
Methods: Cartilage endplate cells were isolated from lumbar intervertebral disc surgical samples and were treated with serum containing a series of concentrations of SAA (2, 5, and 10 ?M) for 24, 48, and 72 h to identify a proper dose and treatment time of SAA. The effect SAA on interlenkin-1β (IL-1β)-induced extracellular matrix degradation of cartilage endplate cells were analyzed by Alcian blue staining and assessment of the expression levels of ADAMTS-5, MMP3 and Col2a1. Further, the potential target miRNAs were preliminarily screened by micro-RNA sequencing combining qRT-PCR and Western blot, and then, the miRNAs mimics and inhibitors were used to verify the regulatory effect of SAA on potential target miRNAs.
Results: The 10 μM SAA treatment for 48 h significantly enhanced the viability of cartilage endplate cells, and increased Col2a1 expression and glycosaminoglycan accumulation that were repressed by IL-1β, and reduced the effect of IL-1β on ADAMTS-5, and MMP3. Screening analysis based on micro-RNA sequencing and Venny analysis identified the downstream micro-RNAs, including miR-940 and miR-576-5p. Then, the miR-940-mimic or miR-576-5p-mimic were transfected into CEPCs. Compared with the SAA group, the expression of ADAMTS-5 and MMP3 increased significantly and the expression of COL2A1 obviously decreased after overexpression of miR-940 or miR-576-5p in CEPCs.
Conclusion: Salvianolic acid A attenuated the IL-1β-induced extracellular matrix degradation of cartilage endplate cells by targeting regulate the miR-940 and the miR-576-5p.
Keywords: Cartilaginous endplates cells; Extracellular matrix; Intervertebral disc; Micro-RNA; Salvianolic acid A.