ObjectiveTo investigate the protective effect of mangiferin on acute spinal cord injury (SCI) in rats and its mechanism. MethodsNinety Sprague Dawley rats were randomly divided into 5 groups, 18 rats in each group. SCI was induced by using the Allen's method (60 g/cm) at T9 level in the rats of groups B, C, D, and E; laminectomy was performed at T8-10 in group A. The rats were injected intraperitoneally with saline in groups A and B, and with mangiferin in groups C (10 mg/kg), D (25 mg/kg), and E (50 mg/kg) every day for 30 days. The survival condition of rats was observed after operation; at 24, 48, and 72 hours after operation, the motor function of the hind limb was evaluated by the Basso, Beattie, Bresnahan (BBB) scores. The spinal cord edema was assessed by measuring the water content in spinal cord tissues at 72 hours. Meanwhile, malondialdehyde (MDA), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH) were detected by ELISA; nuclear factor κB (NF-κB), tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and IL-6 were measured via ELISA at the same time. Caspase-3 and Caspase-9 were also detected by ELISA after mangiferin treatment for 30 days. The expressions of Bax and Bcl-2 proteins were detected by Western blot. Pathological changes of the spinal cord was observed by HE staining. And Caspase-3 protein expression was detected by immunohistochemical staining. ResultsAll rats survived to the end of experiment. BBB scores of groups B, C, D, and E were significantly less than that of group A (P < 0.05), and it showed an increase trend from groups B to E (P < 0.05). The content of water of groups B, C, D, and E were significantly greater than that of group A (P < 0.05), and it showed a decrease trend from groups B to E (P < 0.05). ELISA showed that the activities of MDA, NF-κB, TNF-α, IL-1β, IL-6, Caspase-3, and Caspase-9 in groups B, C, D, and E were significantly greater than that in group A (P < 0.05), and they showed decrease trends from groups B to E (P < 0.05). Meanwhile, the activities of CAT, SOD, and GSH in groups B, C, D, and E were significantly less than that in group A (P < 0.05), and they showed increase trends from groups B to E (P < 0.05). Western blot showed that the relative expression of Bax protein in groups B, C, D, and E were significantly greater than that in group A (P < 0.05), and it showed a decrease trend from groups B to E (P < 0.05). Meanwhile, the relative expression of Bcl-2 protein in groups B, C, D, and E were significantly less than that in group A (P < 0.05), and it showed an increase trend from groups B to E (P < 0.05). Histological observation showed that the pathological changes in group B were accord with that in SCI, and the degree of necrosis in groups C, D, and E were significantly improved when compared with that in group B, and the effect was better in group E than group D, and group D than group C. Immunohistochemical staining showed that the absorbance (A) value of Caspase-3 in groups B, C, D, and E were significantly greater than that in group A (P < 0.05), and it showed a decrease trend from groups B to E (P < 0.05). ConclusionMangiferin has neuroprotective effects on acute SCI in rats by alleviating edema of spinal cord, inhibiting oxidative stress and inflammation response, and regulating the Bcl-2 and Bax pathway.