The effect of lipoxin A4 on radicular pain caused by intervertebral disc herniation / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate the effect of lipoxin A4 LXA4) on radicular pain caused by intervertebral disc herniation.Methods Non-compressive intervertebral disc herniation was induced into forty-eight adult male Sprague-Dawley rats,and they were divided into a sham group (sham operation + 10 μl normal saline),a control group (modeled + 10 μl normal saline),an LXA4 10 ng group (modeled + 10 ng LXA4) and an LXA4 100 ng group (modeled + 100 ng LXA4),with 12 rats in each group.The normal saline (10 μl) or LXA4 (10 μl) was administered intrathecally right after the operation and on each of the three succeeding days.General behavior was observed and the 50％ paw withdrawal threshold (50％ PWT) was measured.On postoperative day 7 all the rats were killed and the ipsilateral lumbar (L4~) segments of their spinal dorsal horns were removed for determination of the expression of p-JNK,t-JNK,p-ERK and t-ERK proteins using western blotting.TNF-α,IL-1β and TGF-β1 expression were determined using ELISA.Results There was no significant difference in the 50％PWT of the sham group before and after surgery,but the 50％ PWTs of the control group and the LXA4 10 ng group were significantly decreased after the operation compared with their values beforehand and significantly lower than the value of the sham group at all time points.Moreover,the 50％ PWT of the LXA4 10 ng group on postoperative days 3 and 5 was significantly higher than the control group;as was the value of the LXA4 100 ng group on postoperative days 2,3,4,5,6 and 7.The p-JNK and p-ERK expression in the control group,the LXA4 10 ng group and the LXA4 100 ng group were all increased significantly more than in the sham group,but their expression in the LXA4 10 ng group and LXA4 100 ng group were decreased significantly more in a dose-dependent manner compared with the control group,with the LXA4 100 ng group showing the greatest decrease.There were no significant differences in t-JNK or t-ERK expression within each group.Conclusion LXA4 can alleviate radicular pain caused by non-compressive lumbar intervertebral disc herniation.The underlying mechanism involves inhibiting the activation of the ERK and JNK pathways,reducing the expression of pro-inflammatory cytokines and increasing the expression of anti-inflammatory cytokines.