Rheumatoid arthritis (RA) is a common inflammatory disease, which significantly reduces the quality of life and increases the risk of cardiovascular and cerebrovascular diseases. The present work studied the therapeutic potency of Salvianolic acid B (Sal-B) for RA and revealed one of the possible underlying mechanisms.

Human rheumatoid fibroblast-like synoviocytes (MH7 A) were treated with Sal-B before, during or after lipopolysaccharide (LPS) stimulation. CCK-8 assay, Annexin V-FITC/PI double-staining, RT-qPCR, Western blotting and ELISA were carried out to measure the changes of cell viability, apoptosis, and the release of pro-inflammatory cytokines. Next, the involvement of miR-142-3p and related signaling pathways in Sal-B-mediated protection was studied.

Sal-B (10 μM) treatment significantly ameliorated LPS injury to MH7 A cells, as cell viability was increased, expression of p53 and p21 was repressed, apoptosis was inhibited, and the release of MCP-1, IL-6 and TNF-α was reduced. However, Sal-B (10 μM) treated alone has no impacts on MH7 A cells in the abovementioned aspects. miR-142-3p was down-regulated by LPS stimulation, while was up-regulated by treatment of Sal-B. Rescue assay results showed that Sal-B did not remit LPS injury when miR-142-3p was silenced. And also, the inhibitory effects of Sal-B on NF-κB and JNK pathways were abolished by miR-142-3p silence.

Sal-B could protect against and reverse LPS-induced injury in MH7 A cells, showing anti-apoptotic and anti-inflammatory capacities. The anti-RA potential of Sal-B might be via up-regulating miR-142-3p, and subsequently modulating NF-κB and JNK pathways.