OBJECTIVETo investigate the effects of complement inhibiting component of Ephedra sinica on immunological inflammation following acute spinal cord injury (SCI) in rats.

METHODSThe complement inhibiting component of Ephedra sinica was isolated by multiple precipitation steps and thin layer chromatography, and then the activity was analyzed. Fifty healthy SD rats were selected and randomly divided into the control group and the experimental group, 25 in each group. Induction of SCI was performed following a modified Allen's weight-drop method. The complement inhibiting component from Ephedra sinica (15 mg/kg) dissolving in 5 mL normal saline was immediately administered by gastrogavage after SCI, once daily. Equal volume of normal saline was administered to rats in the control group by gastrogavage. Hematoxylin and eosin (H&E) staining and C3 immunohistochemical staining were performed in SCI tissue at 12 h, day 1, 3, 7, and 14 after SCI. C3 positive expressions and myeloperoxidase (MPO) activity were assessed. Intercellular adhesion molecule-1 (ICAM-1) mRNA expression level was evaluated by Real-time PCR technique.

RESULTSC3 positive expression, MPO activity, and ICAM-1 mRNA level were significantly weaker in the Ephedra sinica group than in the control group at all time points (12 h, day 1, day 3, day 7, and day 14 after SCI) (P < 0.01, P < 0.05).

CONCLUSIONSThere existed complement system activation following acute SCI. The complement inhibiting component of Ephedra sinica significantly reduced immunological inflammation after SCI, and played an important role in secondary SCI.