Expression of TLR4/MyD88/NF-κB pathway genes and its related inflammatory factors in secondary spinal cord injury

Abstract

To investigate the expression of Toll-like receptor 4 (TLR4)/myeloid differentiation factor (MyD88)/nuclear factor-κB (NF-κB) pathway genes and related inflammatory factors tumor necrosis factor-α (TNF-α), interleukin (IL)-12, IL-6 in patients with secondary spinal cord injury (SSCI) and the correlations with prognosis. The clinical data of 105 SSCI patients and 40 healthy subjects were reviewed. According to Frankel's classification of spinal cord injury, the patients were divided into complete injury group and incomplete injury group, and according to the improvement of Japanese Orthopedic Association (JOA) scores, the patients were divided into good prognosis group and poor prognosis group. The expression of TLR4, MyD88, NF-κB in peripheral blood mononuclear cells (PBMC) and serum TNF-α, IL-12, IL-6 levels were compared between SSCI patients and healthy controls, between patients with complete and incomplete injury, between patients with poor and good prognosis. Logistic regression analysis was used to analyze the risk factors leading to poor prognosis of SSCI, and Pearson's correlation analysis was used to analyze the correlation between JOA score and the above indicators. The expressions of TLR4, MyD88, NF-κB in PBMC and serum TNF-α, IL-12, IL-6 levels in SSCI patients were significantly higher than those in healthy subjects (all P<0.01), those in complete injury group were higher than those in incomplete injury group, and those in poor prognosis group were higher than those in good prognosis group (all P<0.01). The proportions of patients with Frankel grade A, spinal cord edema or hemorrhage, spinal cord injury length longer than 4 cm in poor prognosis group was significantly higher than those in good prognosis group (all P<0.01). Logistic regression analysis showed that Frankel grade, spinal cord edema or hemorrhage, length of spinal cord injury, relative expressions of TLR4, MyD88, NF-κB in PBMC, serum levels of TNF-α, IL-12 and IL-6 were risk factors for poor prognosis in SSCI patients (P<0.05 or P<0.01). Pearson's correlation analysis showed that JOA improvement rate was negatively correlated with the relative expressions of TLR4, MyD88, NF-κB mRNA in PBMC and serum TNF-α, IL-12, IL-6 levels (P<0.05 or P<0.01). The activation of TLR4/MyD88/NF-κB pathway and the up-regulation of the expression of related inflammatory factors TNF-α, IL-12 and IL-6 are involved in the progression of SSCI, which are closely related to the neuroinflammatory injury, and can be used as reference indexes for evaluating prognosis in SSCI patients.