Effect of low-level laser irradiation on expression of TNF-α, IL-6 and IL-10 after acute spinal cord injury in rats

Spinal cord injury (SCI) model is created by Allen's method, and this study is designed to explore the effect of 810 nm low-level laser irradiation on expressions of TNF-α, IL-6 and IL-10 in acute spinal cord injury. 68 SD rats are randomly divided into normal group, SCI group and irradiation group. Light (810 nm, 150 mW) is applied transcutaneously at the lesion site of rats in irradiation group. Functional recovery is assessed by open-field test (BBB test) on 1 d, 3 d, 7 d after injury. The expressions of TNF-α, IL-6 and IL-10 in the injured spinal cords are examined by enzyme linked immuno sorbent assay (ELISA) method at the time of 1 h, 3 h, 6 h, 12 h, 1 d, 3 d, 5 d and 7 d after injury. We find that there is a statistically significant functional recovery (P<0.05) in the irradiation group compared to SCI group at 7 d. The expressions of TNF-α and IL-6 of irradiation group is significantly lower than the comparable SCI group at the time of 6 h, 12 h, 1 d (TNF-α) and 6 h, 12 h, 5 d (IL-6) (P<0.05). The expression of IL-10 of Laser group is significantly higher than the comparable SCI group at the time of 1 d, 3 d, 5 d and 7 d (P<0.05). There is no statistical difference at other time points. The results of our study show that laser irradiation can effectively inhibit the expression of pro-inflammatory cytokine TNF-α and IL-6 and significantly promote the expression of IL-10 in rats of acute spinal cord injuries, and laser irradiation can promote functional recovery of acute spinal cord injury rats.