[Electroacupuncture of "Jiaji" (EX-B2) inhibits inflammatory response by regulating HMGB1/TLR4/NF-κB signaling pathway in rats with spinal cord injury].

Objectives: To observe the effect of electroacupuncture (EA) of "Jiaji" (EX-B2) on expression of high mobility group box 1 (HMGB1)/Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) related proteins and inflammation-related factors in spinal cord injury (SCI) rats, so as to explore the dynamic process of inhibiting inflammatory response in rats with SCI, and to provide a new idea and theoretical basis of molecular biology for the treatment of SCI.
Methods: Fifty-four SD rats were randomly divided into sham operation, model, and EA groups ( n =18 in each group), which were further divided into 3 d, 7 d and 14 d subgroups, with 6 rats at each time point. The SCI model was established according to the Allen's method. Rats in EA group received EA (1 mA, 100 Hz) intervention at EX-B2 of T9 and T11 24 hours after modeling for 30 min, once a day for 3 d, 7 d, or 14 d, respectively. The motor function of rats' hind limbs was evaluated using BBB scale, the morphological structure of rats' spinal cord tissue was observed by H.E. staining. The contents of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in spinal cord tissue were detected by ELISA. Western blot and immunofluorescence staining were used to detect the relative protein expression and fluorescence positive expression of HMGB1, TLR4 and NF-κB p65 in spinal cord tissue, respectively.
Results: Compared with the sham operation group, the BBB scores after modeling and on day 3, 7 and 14 were all decreased ( P <0.05), while the contents of iNOS and COX-2 in spinal cord tissue, the protein expression and fluorescence positive expression of HMGB1, TLR4, and NF-κB p65 were increased ( P <0.05) in the model group. In comparison with the model group, the BBB scores on day 3, 7 and 14 were obviously increased ( P <0.05), while the contents of iNOS and COX-2, the protein expression and fluorescence positive expression of HMGB1, TLR4, and NF-κB p65 were significantly down-regulated in the EA group ( P <0.05).
Conclusions: EA of "Jiaji" can promote the recovery of SCI neurological function, which may be related to its function in regulating the HMGB1/TLR4/NF-κB signaling pathway, down-regulating the expression of iNOS and COX-2, and inhibiting the neuroinflammatory response after SCI.