ABSTRACT
Objective To investigate the feasibility of NR2B small interference RNA(NR2B siRNA)carried by water-soluble lipopolymer(WSLP)for treatment of neuropathic pain in rats.Methods One hundred healthy male SD rats weighing 180-200 g were randomly divided into 5 groups(n=20 each):normal control group (group C),sham operation group(group S),neuropathic pain group(group NP),group WSLP-NR2B siRNA (group W)and group WSLP-negative NR2B siRNA(group WN).Neuropathic pain was induced by partial ligation of sciatic nenre.WSLP-NR2B siRNA complex was formed by binding WSLP and NR2B siRNA.Normal saline.WSLP-NR2B siRNA complex and WSLP-negative NR2B siRNA 20μl were injected intrathecally after operation in NP,W and WN groups respectively.Mechanical withdrawal threshold(MWT)and thermal withdrawal duration (TWD)were measured before(baseline)and at 3,7,14 and 21 days after operation.Ten animals in each group were sacrificed on the 3rd day after operation and the lumbar segment(L4-6)of the dorsal root ganglia was removed for determination of the expression of NR2B mRNA and protein using RT-PCR and Western blot analysis.Results Sciatic nerve ligation significantly decreased MWT and prolonged TWD and increased NR2B mRNA and protein expression in group NP as compared with group C.WSLP-NR2B siRNA complex significantly reduced sciatic nerve ligation-induced hyperalgesia and decreased NR2B mRNA and protein expression in group W as compared with group NP.Conclusion WSLP not only mediates NR2B siRNA successfully and inhibits the expression of NR2B,but also reduces neuropathic pain in rats.