Modulation of Neuroinflammation by Taklisodok-um in a Spinal Cord Injury Model

Chronic neuroinflammation after spinal cord injury (SCI) is associated with spinal cord damage and functional impairment. In patients, SCI is associated with severe disability, an extensive rehabilitation requirement, and high cost burden. Moreover, there is no effective treatment for SCI. Taklisodok-um (TLSDU) is a traditional herbal medicine used in Korea and China to facilitate detoxification and drainage. This study investigated the therapeutic effect of TLSDU after SCI.

Seven-week-old ICR mice (male, 20-30 g) underwent hemi-transection in the T9-10 segment of the spinal cord and were divided into 3 groups: sham, SCI + control treatment, and SCI + TLSDU treatment. TLSDU treatment was initiated the day after SCI surgery and administered once daily for 3 weeks at an oral dose of 1.2 mg/g. The mice were weighed for 3 weeks. At the age of 10 weeks, all mice were sacrificed and immunohistochemistry and Western blotting were performed.

We found that TLSDU facilitated healthy weight gain and attenuated the expression of neuroinflammatory markers. GFAP and Iba-1 expression levels were downregulated in the spinal cords of TLSDU-treated SCI mice as compared to control SCI mice. Additionally, pro-inflammatory proteins CD11b and BAX were induced in control SCI mice, but their expression was attenuated in TLSDU-treated SCI mice. Finally, we found that the expression of TLR4 signaling pathway-related proteins was downregulated in TLSDU-treated SCI mice as compared to control SCI mice.

These findings suggest that TLSDU attenuates neuroinflammation after SCI in part by regulating TLR4 signaling at the injury site.