HSYA alleviates secondary neuronal death through attenuating oxidative stress, inflammatory response, and neural apoptosis in SD rat spinal cord compression injury

Background: Hydroxysafflor yellow A (HSYA) is a major active component of yellow pigment extracted from safflowers; this compound possesses potent neuroprotective effects both in vitro and in vivo. However, underlying mechanism of HSYA is not fully elucidated. The present study investigated the protective effects of HSYA in rat spinal cord compression injury model and related mechanisms involved. Methods: Sprague-Dawley rats were divided as Sham, Control, and HSYA groups (n=30 per group). Spinal cord injury (SCI) model was induced by application of vascular clips (force of 50 g, 1 min) to the dura at T9-T10 level of vertebra. Injured animals were administered with either HSYA (8 mg/kg at 1 and 6 h after injury, then 14 mg/kg, for a total of 7 days at 24-h time intervals) or equal volume of saline by intraperitoneal injection. Results: From this experiment, we discovered that SCI in rats resulted in severe trauma, which is characterized by tissue damage, lipid peroxidation, neutrophil infiltration, inflammation mediator release, and neuronal apoptosis. However, HSYA treatment significantly reduced the following: (1) degree of tissue injury (histological score) and edema; (2) neutrophil infiltration (myeloperoxidase activity); (3) oxidative stress (superoxide dismutase, malondialdehyde, and nitric oxide); (4) pro-inflammatory cytokine expression (tumor necrosis factor-alpha, interleukin-6, inducible nitric oxide synthase, cyclooxygenase-2); (5) nuclear factor-kappa B activation; (6) apoptosis (terminal deoxynucleotidyl transferase dUTP nick end labeling staining and cysteine-aspartic protease-3 activity). Moreover, in a separate set of experiments, we clearly demonstrated that HSYA treatment significantly ameliorated recovery of limb function (as evaluated by Basso, Beattie, and Bresnahan behavioral recovery scores). Conclusions: Treatment with HSYA restrains development of oxidative stress, inflammation response, and apoptotic events associated with SCI of rats, demonstrating that HSYA is a potential neuroprotectant for human SCI therapy.