| Objectives：To investigate the effects of intra-CA1 administration of miR-181 c alleviates neuralgia in CCI rats by down-regulating TRIM2 and increasing NR1 receptor expression.Methods:1.Sprague-Dawley male rats were randomized into four groups: Sham group,CCI goup,CCI+ miR-181 c agomir group,CCI+ miR-181 c antagomir group.Mechanical withdrawal latency(MWL)was evaluated before the surgery and on 1,3,5,7,10 and 14 day after surgery.2.We examined the role of the CCI on mood and exploration of the novel environment using the elevated plus-maze test and sucrose consumption test and Y-maze behavioral.3.Morphological changes of rat hippocampal CA1 neurons were observed by Nissl staining.4.The expression of NF-L in the CA1 region of rat hippocampus was observed by immunohistochemistry.5.The expression of TRIM2,NF-L,NR1,GAP-43 and SYN-1 was detected by western blot.6.Golgi staining was used to evaluate the survival neurons in hippocampus and total dendritic length,branch complexity,dendritic spine density of top dendrites of neurons in CA1.Results:1.MWL in CCI group was significantly lower than that of the sham group(P<0.05).Repeated administrated of miR-181 c agomir attenuate CCI-induced mechanical hyperalgesia(P<0.05)and miR-181 c antagomir enhanced CCI-induced mechanical hyperalgesia(P<0.05).2.Y maze experiment showed that the exploration behavior and spatial recognition ability of CCI rats were decreased compare with Sham group(P< 0.05);Compare with CCI rats,the exploratory behavior and spatial recognition ability of rats were increased 7and 14 days after treatment with miR-181 c agomir(P< 0.05),while the exploratory behavior and spatial recognition ability of rats were further decreased after treatment with miR-181 c antagomir(P< 0.05).3.Sucrose consumption testshowed that CCI rats had a decreased preference for sugar and water 10 d after operation compare with Sham group(P< 0.05).Compare with CCI rats,miR-181 c agomir treatment significantly increased sugar water preference on 7 and10 days(P< 0.05);However,in miR-181 c antagomir group,sugar water preference decreased significantly on 10 days(P< 0.05).4.Elevated plus-maze showed that,compare with Sham group,the proportions of open-arm residence time and open arm number decreased at 10 d and 14 d after CCI(P<0.05).Compare with CCI group,the proportions of open arm residence time and open-arm times in miR-181 c agonist intervention group were increased(P<0.05);However,the proportion of open arm residence time and open arm times in the miR-18 c inhibitor intervention group further decreased.5.Nissl staining demonstrated that,compare with sham group,the number of surviving neurons in the hippocampus CA1 regions of the CCI group were significantly decreased(P<0.05).Compare with CCI group,Administration of miR-181 c agomir reversed the morphologic changes and increased the number of normal neurons(P<0.05).There was more neuron loss in the CCI+ miR-181 c antagomir group compared with the CCI group(P<0.05).6.Immunohistochemistry staining revealed that NFL was significantly reduced in CCI rats and was increased after miR-181 c agomir treatment.7.WB results demonstrated that,for the CCI rats,the expression of TRIM2 in hippocampal tissue was significantly increased compared with sham group(P<0.05),while the expression of NF-L and NR1 were significantly decreased compared with sham group(P<0.05).Administration of miR-181 c agomir reversed CCI-induced the increased expression of TRIM2 and the decreased expression of NF-L and NR1(P<0.05).However,Administration of miR-181 c agomir enhanced CCI-induced the increased expression of TRIM2 and the decreased expression of NF-L and NR1(P<0.05).8.Golgi staining showed that the number of hippocampal neurons in CCI rats decreased,and The total length,branch complexity and dendritic spine density of top dendrites of neurons in hippocampus CA1.After administration of miR-181 c agonist,neuronal injury and dendrite injury were alleviated,and dendrite branching was dense(P<0.05).However,after the administration of miR-181 c inhibitor,the neuronal injury was further aggravated,and the dendritic injury was aggravated,and the dendritic branches were sparse.Conclusions:Intra-hippocampal CA1 injection of miR-181 c agomir attenuated CCI-induced mechanical hyperalgesia,reduce depressive and anxious behavior,improve cognitive performance,reduced the TRIM2 expression and enchanced NF-L and NR1 expression level with alleviate hippocampal neuron and dendrite injury. |
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