Antioxidant effects of curcumin in unilateral spinal cord injury model in adult male rats

Inflammatory responses and oxidative stress (OS) play a significant role in the development of spinal cord injury (SCI), as evidenced by both pre-clinical and clinical studies. This research aimed to assess the potential antioxidant and anti-inflammatory properties of curcumin (CuC) as a therapeutic approach in a unilateral SCI model using male rats. We used 40 adult male Wistar rats (each weighing 220 – 250 g) that were randomly assigned to one of the five experimental groups: (1) Control (Con), (2) Model (SCI animals), (3) Model+CuC20, (4) Model+CuC40, and (5) Model+CuC80. Accordingly, the SCI animals in Model+CuC20, Model+CuC40, and Model+CuC80 groups received 20, 40, and 80 mg/kg/day of CuC through the intraperitoneal route, respectively. We assessed functional recovery, measured OS indicators, including malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and total antioxidant capacity (TAC) in the blood, and evaluated protein levels of caspase 1, NOD-like receptor family pyrin domain-containing 3 (NLRP3), and apoptosis-associated speck-like protein containing a CARD (ASC) in the spinal cord tissue. The CuC treatment groups showed a significant enhancement in functional recovery, a marked decrease in MDA levels, and a notable elevation in SOD activity relative to the SCI animals. Model+CuC40 and Model+CuC80 animals exhibited a significant improvement in GSH activity and TAC level as compared to the SCI animals. The results also showed a dramatic decrease in the protein concentration of NLRP3, ASC, and Casp1 in the Model+CuC40 and Model+CuC80 groups relative to the Model group (P < 0.0001). In conclusion, the treatment with CuC significantly enhanced functional recovery in SCI rats by effectively mitigating OS and reducing inflammatory markers.