Effect of vitexin on motor function and inflammation in rats with spinal cord injury

Objective: To investigate the effect of vitexin(VT) on spinal cord injury(SCI) rats and lipopolysaccharide(LPS)-induced BV2 microglia. Methods: In vivo experiments: SD rats were divided into sham-operated group(sham group), model SCI group(model group) and VT low-dose, VT medium-dose and VT high-dose groups. Basso-Beattie-Bresnahan(BBB) score was used to evaluate the motor function of rats; reverse transcription-quantitative PCR(RT-qPCR) and enzyme-linked immunoassay(ELISA) were used to detect the gene and protein expression of inflammatory factors in rats; hematoxylin-eosin(HE) staining was used to observe the spinal cord tissue structure. In vitro experiments: BV2 microglia were divided into normal control group(control group), LPS group, VT low-dose, medium-dose and high-dose groups and VT high-dose alone administration group; LPS-induced BV2 microglia activation was used to construct in vitro neuroinflammation model; cell counting kit-8(CCK-8) method was used to screen the range of safe concentration of VT; RT-qPCR and western blotting were used to detect the levels of cellular inflammatory gene and protein expression. Results: In vivo experiments: compared with the SCI group, the BBB scores of the VT medium-and high-dose groups were significantly higher, and the score of the VT medium-dose group was significantly higher than that of the high-dose group on the 7th day of the injury(both P<0.05); the expression of TNF-α mRNA in the VT medium-dose group was lower compared with that of the SCI group, and the expression of IL-10 mRNA in the VT medium-and highdose groups was significantly higher compared with that in the SCI group(both P<0.05); the protein levels of TNF-α in the VT low-dose group, VT medium-dose group and VT high-dose group were significantly decreased(all P<0.05), and the protein levels of IL-10 in the VT dose groups were significantly increased(all P<0.05);HE results showed that the spinal cord in the sham group was structurally intact, with more neurons and a more regular arrangement; spinal cord tissue in the SCI group was infiltrated with inflammatory cells, showed more cavities, and neurons were reduced and atrophied with irregular arrangement; compared with the SCI group, the damage in the VT treatment group was smaller, and the reduction of inflammatory infiltration was more obvious.In vitro experiments: compared with the LPS group, TNF-α mRNA expression was significantly reduced in each dose group of VT(all P<0.05), and reduced in a dose-dependent manner; TNF-α protein expression was reduced in each group of VT(all P<0.001). Conclusion: VT inhibits the inflammation of rats, reduces the histopathological damage of the spinal cord, and improves the local microenvironment of the spinal cord after injury, thereby protecting the damaged spinal cord neurons, and promoting the recovery of motor function.