| Objective To observe the effect on neuropathic pain after silence of Reelin expression in rats, and discuss the mechanism.Methods Male Sprague-Dawley rats, age 8-10 weeks, weighing 200-250 g. 66 intrathecal catheter without motor dysfunction, were randomly divided into 6 groups using a random number table, ie, Sham group(n=12), CCI group(n=12), RNAi group(n=12), EV group(n=12), lithium chloride(Li Cl) group(n=9) and Li Cl+RNAi group(n=9). Chronic sciatic nerve constrictive injury(CCI) rats modle was induced by right ligation of sciatic nerve. The rats in sham group were only exposed the sciatic nerve without ligation. LV-Reelin-RNAi was injected intrathecally on day 1 after operation in RNAi group and Li Cl+RNAi group(5 ?L, 1×108 TU/m L). The negative control virus was injected in EV group(5 ?L, 1×108 TU/m L), while the equal volume of normal saline was given in others groups. Intrathecal injection Li Cl was completed(5 ?L, 4 mol/L) in Li Cl group and Li Cl+RNAi group on operation day and day 1, 2, 3, 4, 5, 6 after operation. The paw withdrawal thermal latency(PWTL) and paw withdrawal mechanical(PWMT) were measured on day 1 preoperation and day 1, 4, 7, 10, 14, 17, 21 postperation. Then the rats were sacrificed and intumescentia lumbalis of the spinal cord were removed for observed NR2 B expression location and intensity by immunohistochemical. The operation side intumescentia lumbalis of the spinal cord were removed for detection of NR2 B, GSK-3? and p-GSK-3? expression by Western blot on day 10 after operation.Result(1) Pain behaviors: PWTL and PWMT were significantly decreased after operation in operation side(P<0.05). PWTL and PWMT were further decreased in operation side in RNAi group until day 7 to 21 after operation(P<0.05), the contralateral was no obvious effect(P>0.05). PWTL and PWMT were significantly increased after intrathecal injection Li Cl began to day 4 after operation(P<0.05). There was no significant difference between EV and CCI groups(P>0.05).(2) Western blot: The expression of p-GSK-3?/GSK-3? ratio was significantly decreased on operation side spinal dorsal horn on day 10 after CCI operation(P<0.05). The ratio was further decreased after RNA interference(P<0.05). The intrathecal injection Li Cl up-regulated this ratio; meanwhile, the expression of NR2 B was significantly increase(P<0.05). NR2 B was further increased after RNA interference(P<0.05). The intrathecal injection Li Cl can inhibited the up-regulation of NR2 B expression. There was no significant difference between EV and CCI groups(P>0.05).(3) Immunohistochemical: NR2 B was located in superficial laminae of spinal dorsal horn. NR2 B expression was up-regulatedon operation side spinal dorsal horn on day 10 after CCI operation(P<0.05). NR2 B was distinctly increased after RNA interference(P<0.05), and the expression of NR2 B was inhibited after intrathecal injection Li Cl(P<0.05).Conclusion Silence of Reelin aggravates the neuropathic pain, which the mechanism may be related with up-regulation of NR2 B by activation of GSK-3?. |
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