Salvianolic acid B reduces acute spinal cord injury and promotes the motor function recovery in rats with spinal contusion

Abstract

Objective To investigate the effect of salvianolic acid B (Sal B) against the secondary spinal cord injury and on the motor function recovery in rats with contusive spind cord injury (SCI). Methods Forty-eight rats with contusive SCI received intraperitoneal injections of Sal B at different doses (2, 10, and 20 mg/kg, n=12) or PBS as control (n=12). Myeloperoxidase (MPO) activity in the spinal cord was determined using colorimetric method 4 h after SCI. Immunohistochemical staining was used to detect the expressions of matrix metallopeptidase 1 (MMP-1) and the cellular proto-oncogene c-Fos 1 d after SCI. The water content in the injured segment of the spinal cord was estimated 3 days atter SCI, and the BBB scores were used to assess the motor function recovery 10 days after SCI. Results High-dose (20 mg/kg) Sal B treatment significantly reduced the MPO activity in comparison with that in the control group (P<0.05). A statistical difference in the BBB scores was noted between the Sal B-treated and control rats 14 days after the treatment (P<0.05). The spinal cord levels of MMP-1 and c-Fos were significantly reduced in high-dose Sal B-treated rats as compared with those in the control rats. Edema in the injured spinal cord was significantly alleviated in high-dose Sal B group in comparison with that in the control group (P<0.05). The BBB scores also differed significantly between the high-dose Sal B and control groups 7 days after the treatment (P<0.05). The improvements of the all the indexes showed positive correlations to the dose ofSal B administered. Conclusion Sal B can alleviate the secondary neural tissue injuries following SCI by attenuating MPO activity, lowering the expressions of MMP-1 and c-Fos and reducing the water content in the injured spinal cord. Sal B also promotes the recovery of limb motor function in rats following SCI. Key words: Acute spinal cord injury; Salvianolic acid B; Secondary injury Myeloperoxidase