Salvianolic acid B promotes bone formation by increasing activity of alkaline phosphatase in a rat tibia fracture model: a pilot study

BACKGROUND: Radix Salviae miltiorrhizae is a herb frequently used within traditional Chinese medicine for the treatment of cardiovascular- and trauma-related diseases. Danshen is the dried root of Salviae miltiorrhizae, from which the polyphenolic compound Salvianolic acid B (Sal B) can be obtained. Sal B is a key component of Danshen. The aim of this study was to determine the effect of Sal B on the healing of long bones following trauma in a rat tibia fracture model. METHODS: Tibia fractures were created in 20 male Sprague Dawley rats. The animals were divided into two groups: (1) experimental group (n = 10); and (2) control group (n = 10). Rats in the experimental group were intraperitoneally administered with Sal B (40 mg/kg/d) for 3 weeks, while rats in the control group received an identical volume of physiological saline solution, administered in the same way. X-ray photographs were taken of all animals at the time points. Rats were euthanized at weeks 1, 3, 8 and 12 post-fracture. Fracture calluses were measured and callus sections were obtained and stained using hematoxylin and eosin (HE) and the calcium cobalt method. HE stained sections were observed and evaluated according to different grades of bone remodeling. Sections stained using the calcium cobalt method were analyzed with an imagine analysis system. RESULTS: Data showed that callus growth was significantly greater in the experimental group compared with the control group (P < 0.05). Furthermore, histological scores in the Sal B-treated group were statistically higher than in the saline treated group at weeks 1, 3 and 8 post-fracture (P < 0.05). Alkaline phosphatase (ALP) activity was enhanced in the experimental group at weeks 1 and 3 post-fracture (P < 0.05). CONCLUSIONS: Our results suggest that Sal B may accelerate early-stage fracture healing. Increased activity of ALP may be one factor which promotes the healing process. This pilot study provides brief insight into the effect of Sal B in fracture healing. These findings will contribute to the development of more and enhanced treatment options for trauma fracture patients.