Effects of intrathecal TRESK gene recombinant adenovirus on inflammatory responses mediated by chemokine in spinal cord of rats with neuropathic pain

Abstract

Objective To evaluate the effects of intrathecal TRESK gene recombinant adenovirus on inflammatory responses mediated by chemokine in the spinal cord of rats with neuropathic pain (NP) . Methods Thirty-six male Sprague-Dawley rats, weighing 200-250 g, were randomly divided into 6 groups (n=6 each) using a random number table: control group (group C) ; sham operation group (group S) ; NP group; TRESK-overexpressed adenovirus group (group TRESK) ; negative adenovirus group (group Virus) ; normal saline group (group NS) . Spinal nerve injury was produced by exposing the sciatic nerve and its branches and ligation and transection of tibial nerve and common fibular nerve in anesthetized rats.In TRESK, Virus and NS groups, pAd/CMV/V5-DEST-TRESK 25 μl (109 IU/ml) , negative adenovirus 25 μl and normal saline 25 μl were intrathecally injected, respectively.At 1 day before operation (baseline, T0) and 1, 3, 7 and 14 days after operation (T1-4) , the mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency were measured.Six rats in each group were sacrificed after measurement of pain threshold at T3.The L4, 5 segments of the spinal cords were removed for determination of monocyte chemotactic protein-1 (MCP-1) , MIP-2, tumor necrosis factor-alpha (TNF-α) , interleukin-1 beta (IL-1β) and IL-6 mRNA expression by real-time PCR. Results There was no significant difference in thermal paw withdrawal latency at each time point between groups.Compared with C and S groups, MWT at T1-4 in NP and TRESK groups and at T1-3 in Virus and NS groups were significantly decreased, and the expression of MCP-1, MIP-2, TNF-α, IL-1β and IL-6 mRNA was up-regulated in NP, TRESK, Virus and NS groups.Compared with group NP, MWT was significantly increased at T1-4, and the expression of MCP-1, MIP-2, TNF-α, IL-1β and IL-6 mRNA was down-regulated in group TRESK. Conclusion The mechanism by which intrathecal TRESK gene recombinant adenovirus reduces NP is related to inhibition of inflammatory responses mediated by chemokine in the spinal cord of rats. Key words: Potassium channels; Neuralgia; Spinal cord; Receptors, CCR2; Chemokine CXCL2; Inflammatory