Study on salvianolic acid B in the reduction of epidural fibrosis in laminectomy rats

BACKGROUND Epidural fibrosis (EF) is a common complication after laminectomy. Salvianolic acid B (Sal B) is a major bioactive component of a traditional Chinese medical agent, Salvia miltiorrhiza, which has shown anti-inflammatory, anti-fibrotic and anti-proliferative properties. The object of this study was to investigate the effect of Sal B on the prevention of epidural fibrosis in laminectomy rats. METHODS A controlled double-blinded study was conducted in sixty healthy adult Wistar rats that underwent laminectomy at the L1-L2 levels. The rats were randomly divided into 3 groups of 20: (1) Sal B treatment group; (2) Vehicle group; (3) Sham group (laminectomy without treatment). All rats were sacrificed 4 weeks post-operatively. The extent of epidural fibrosis, fibroblast proliferation and the expression of vascular endothelial growth factor (VEGF) and inflammatory factors were analyzed. RESULTS The recovery of all rats was uneventful. In the laminectomy sites treated with Sal B, the dura mater showed no adhesion. Collagen deposition was significantly lower in the Sal B group than the other two groups. In addition, both fibroblast and inflammatory cell counting in the laminectomy sites treated with Sal B showed better grades than the other two groups. The expression of VEGF and inflammatory factors in operative sites also suggested better results in the Sal B group than the other two groups. CONCLUSIONS Sal B inhibits fibroblast proliferation, blood vessel regeneration, and inflammatory factor expression. Thus, Sal B is able to prevent epidural scar adhesion in post-laminectomy rats.