OBJECTIVE To study the mechanism of Wenshen Tongdu Recipe in promoting the recovery of motor function in rats with spinal cord injury.

METHODS A total of 144 SD rats were randomly divided into sham operation group, model group, prednisone group, low-dose Wenshen Tongdu Recipe group, medium-dose Wenshen Tongdu Recipe group, high-dose Wenshen Tongdu Recipe group, 3BDO group, and 3BDO + Wenshen Tongdu Recipe group (medium dose). The rat spinal cord injury model was established by modified Allen's method. Intervention began 1 day after modeling, and the drug was administered continuously for 14 days. During the drug administration period, the motor function of the rats in each group was evaluated by Basso-Beattie-Bresnahan (BBB) score and inclined plane test. On the 3rd, 7th and 14th days after modeling, the pathological changes of the spinal cord tissues of the rats in each group were observed by HE staining; the expression levels of inflammatory factors IL-1β, IL-6, IL-4 and IL-10 in the serum of the rats in each group were detected by ELISA; the expression of Beclin 1, LC3B and p62 proteins was detected by immunohistochemistry; the expression of CD16 and CD206 proteins was detected by immunofluorescence staining; the expression of autophagy-related molecules (Beclin 1, LC3B) and Akt/mTOR pathway-related proteins in the spinal cord tissues was detected by Western blot.

RESULTS Compared with the model group, the BBB score and angle of the inclined board test of rats in the medium-dose Wenshen Tongdu Recipe group were increased, and the disordered arrangement of spinal cord tissue, spinal cord vacuoles and inflammatory infiltration were significantly improved, especially on the 14th day. Compared with the sham operation group, the expression levels of serum IL-1β and IL-6 in the model group increased (P < 0.01), and the expression levels of IL-4 and IL-10 decreased (P < 0.05, P < 0.01); compared with the model group, the levels of IL-1β and IL-6 in the Wenshen Tongdu Recipe group were significantly decreased (P < 0.01), and the levels of IL-4 and IL-10 were significantly increased (P < 0.05, P < 0.01); compared with the Wenshen Tongdu Recipe group, the serum IL-1β and IL-6 concentrations of mice in the 3BDO group increased (P < 0.01), and the level of IL-10 decreased (P < 0.05). Compared with the sham operation group, the M1/M2 ratio, P62 protein expression, p-Akt/Akt and p-mTOR/mTOR ratios in the spinal cord tissue of the rats in the model group were significantly increased (P < 0.05, P < 0.01), and the relative protein expression of Beclin1 was decreased (P < 0.01); compared with the model group, the M1/M2 ratio, p-Akt/Akt and p-p70S6K/p70S6K ratios in the Wenshen Tongdu Recipe group were significantly decreased (P < 0.01). Compared with the model group, the Beclin1 protein level in the 3BDO group was decreased, and the p-Akt/Akt and p-mTOR/mTOR ratios were increased (P < 0.05, P < 0.01). Compared with the Wenshen Tongdu Recipe group, the M1/M2 ratio in the 3BDO group and the 3BDO + Wenshen Tongdu Recipe group increased (P < 0.01), the positive rates of Beclin1 and LC3B proteins in the 3BDO group decreased significantly (P < 0.01), and the p-p70S6K/p70S6K ratio in the 3BDO + Wenshen Tongdu Recipe group increased significantly (P < 0.01).

CONCLUSION Wenshen Tongdu Recipe may regulate microglial polarization through Akt/mTOR signaling pathway to activate autophagy, promote the secretion of anti-inflammatory factors, reduce the release of pro-inflammatory factors, alleviate neuroinflammatory response, and thus promote spinal cord injury repair.