Protective effects and potential mechanism of salvianolic acid B on sodium laurate-induced thromboangiitis obliterans in rats

Background: The root of Salvia miltiorrhiza f. alba (RSMA) (Lamiaceae) is used for the treatment of patients with thromboangiitis obliterans (TAO) in traditional Chinese medicine. Previously, a mixture of phenolic acids extracted from RSMA has shown significant protective effects on TAO rats. Purpose: This study investigates the inhibitory effects of salvianolic acid B on TAO induced by sodium laurate injection in rats to explore the effective constituents of RSMA in TAO treatment. Methods: TAO rats were developed using injected sodium laurate. After treatment with ligustrazine hydrochloride (15 mg/kg) and various doses of salvianolic acid B (10, 20, 40 mg/kg) by tail intravenous injection, levels of thromboxane B-2 (TXB2), 6-keto-prostaglandin F-1 alpha (6-keto-PGF(1 alpha)) and endothelin-1 (ET-1) in plasma were determined using enzyme-linked immunosorbent assay. The right femoral arteries were studied by hematoxylin and eosin staining and immunohistochemical analysis to determine pathological changes and overexpression of tumor necrosis factor (TNF)-alpha and inducible nitric oxide synthase (iNOS) in the femoral artery walls of TAO rats. Results: Salvianolic acid B significantly decreased the expressions of TXB2 and ET-1 and increased the expression of 6-keto-PGF(1 alpha), in plasma, and significantly inhibited the overexpression of TNF-alpha and iNOS in the femoral artery walls of TAO rats at medium and high doses. Conclusion: Salvianolic acid B has a protective effect on TAO rats. The mechanism may involve inhibition of thrombosis and TAO-associated inflammatory responses, which may explain the success of RSMA treatment of TAO in humans in traditional Chinese medical practice. Hence, it may be a potential drug for TAO treatment in conventional medicine.