The effect of Resolvin D1 on the radicular pain induced by herniated nucleus pulposus / 中华物理医学与康复杂志

ABSTRACT

Objective To investigate the analgesic effect of Resolvin D1 (RvD1) on radicular pain induced by herniated nucleus pulposusand its underlying mechanism.Methods Fifty-six male rats were randomly divided intoa sham group,a model group,a 10 ng group anda 100 ng group,each of 14.The rat model of non-compressive lumber disc herniation was established in all except the sham group.The former two groups were then injected with 10 μl of phosphate buffer solution (PBS) while the latter 2 groups were injected with 10 μl of PBS containing 10 and 100 ng of RvD1 respectively daily for three successive days.The rats' 50％ paw withdrawal threshold (PWT) was evaluated 1 day before and on 7 successive days after surgery.On day 7 the rats' spinal cords were removed to assess the expression of tumor necrosis factor-or (TNF-α),interlukin-1β (IL-1β) and interlukin-10 (IL-10) using ELISA methods.The levels of ERK and NF-κB/p65 were measured using Western blotting.Results Theaverage 50％PWT of the model group decreased significantly from day 1 to day 7 compared with the sham group,but was significantly lower thanthe RvD1 10 ng group from day 3 to day 7.Moreover the 50％PWT in the RvD1 100 ng group increased significantlyfrom day 2 to day 7 compared with the model group (P＜0.05).The average expression of both TNF-α and IL-1β of the model group was upregulated significantly and that of IL-10 decreased significantly compared with the sham group.Compared with the model group,the expression of TNF-α and IL-1β decreased significantly (P＜0.05)and the level of IL-10 was significantlyup-regulated (P＜0.05) both in the RvD1 10 ng group and 100 ng group.Moreover,the changes were larger in the RvD1 100 ng group (P＜0.05).Compared with the sham group,the levels of p-ERK and NF-κB/p65 in the model group were significantly up-regulated (P＜0.05).Compared with the model group,intrathecal injection of RvD1 (10 ng or 100 ng) significantly decreased the expressions of p-ERK and NF-κB/p65 (P＜0.05).Moreover,the decrease wasgreater in the RvD1 100 ng group (P＜0.05).Conclusions RvD1 might alleviate the radicular inflammation and pain byregulating the balance of inflammatory mediators and activation of p-ERK and NF-κB/p65 pathways.It may offer novel therapeutic approaches for the management of lumbar disc herniation.