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OBJECTIVE@#To explore the analgesic mechanism of intrathecal trichostatin A (TSA) injection in a rat model of neuropathic pain induced by chronic constrictive injury (CCI).@*METHODS@#Male SD rats were randomized into sham operation+ DMSO group (group S), CCI +DMSO group (group C), CCI +10 μg TSA group (group T), and in the latter two groups, rat models of neuropathic pain were established induced by CCI. The rats were given intrathecal injections of 10 μL 5% DMSO or 10 μg TSA (in 5% DMSO) once a day on days 7 to 9 after CCI or sham operation. The rats were euthanized after behavioral tests on day 10, and the lumbar segment of the spinal cord was sampled to determine the expression of histone deacetylase 4 (HDAC4) protein and mRNA and detect the differentially expressed miRNAs using a miRNA chip. MiR-190b-5p and miR-142-3p were selected for validation of the results using RT-qPCR.@*RESULTS@#Compared with those in group S, the rats in group C showed significantly decreased paw withdrawal mechanical threshold (PWMT) from day 3 to day 10 after CCI ( < 0.05); intrathecal injection of TSA significantly reversed the reduction of PWMT following CCI ( < 0.05). Positive HDAC4 expression was detected mainly in the cytoplasm of the neurons in the gray matter of the spinal cord, and was obviously up-regulated after CCI ( < 0.05). Intrathecal injection of TSA significantly suppressed CCI-induced up-regulation of HDAC4 at 10 days after the operation ( < 0.05). Compared with the miRNA profile in group S, miRNA profiling identified 83 differentially expressed miRNAs in group C (fold change ≥2 or ≤0.5, < 0.05); TSA treatment reversed the expressions of 58 of the differentially expressed miRNAs following CCI, including 41 miRNAs that were decreased after CCI but up-regulated following TSA treatment. The results of real-time PCR validated the changes in the expressions of miR-190b-5p and miR-142-3p.@*CONCLUSIONS@#TSA suppresses CCI-induced up-regulation of HDAC4 and reverses differential expressions of miRNAs in the spinal cord of rats, which may contribute to the analgesic effect of TSA on neuropathic pain.
Subject(s)
Animals , Male , Rats , Histone Deacetylases , Hydroxamic Acids , MicroRNAs , Rats, Sprague-Dawley , Spinal Cord , Up-RegulationABSTRACT
Objective To evaluate the effect of intrathecal ropivacaine on spinal histone deacetylase 1 (HDAC1) and HDAC2 expression in the rats with neuropathic pain (NP).Methods Thirty adult male Sprague-Dawley rats, weighing 220-250 g, in which intrathecal catheters were successfully placed, were randomly divided into 3 groups (n=10 each) using a random number table: sham operation group (group S), group NP, and NP + ropivacaine group (group R).NP was induced by chronic constriction injury (CCI) in anesthetized rats.Sciatic nerve was exposed and 4 loose ligatures were placed on the left sciatic nerve at 1 mm intervals with 4-0 chromic catgut.Starting from 7th day after CCI, 0.25％ ropivacaine 20 μl was injected intrathecally in group R, while the equal volume of normal saline was given instead of ropivacaine in S and CCI groups once a day for 7 consecutive days.At 1 day before CCI (T0) ,and 3, 7, 10, 14, 17 and 21 days after CCI (T1-6) , the mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured.After the pain threshold was measured at T4,3 rats from each group were sacrificed, and their lumbar enlargements were harvested for determination of the expression of HDAC1 and HDAC2 by Western blot.Results Compared with group S, the MWT was significantly decreased, and the TWL was shortened at T2-6, and the expression of HDAC 1 and HDAC2 was up-regulated at T4 in NP and R groups (P＜0.05).Compared with group NP, the MWT was significantly increased at T4, and the TWL was prolonged at T3.4, and the expression of HDAC1 and HDAC2 was downregulated at T4 in group R (P＜0.05).Conclusion The mechanism by which intrathecal ropivacaine alleviates NP may be related to inhibited up-regulation of spinal HDACI and HDAC2 expression in rats.
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Objective To evaluate the role of histone deacetylase in the spinal cord in the maintenance of neuropathic pain (NP) in rats.Methods Twenty-seven male Sprague-Dawley rats,weighing 230-270 g,were randomly divided into 3 groups (n =9 each) using a random number table:sham operation group (group S),group NP,and NP + intrathecal Trichostatin A (TSA) group (group T).NP was induced by chronic constrictive injury.At 7 days after operation,5％ DMSO,5％DMSO and TSA 10 μg (10 μl) were injected intrathecally once a day for 3 consecutive days in S,NP and T groups,respectively.Mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 1 day before operation and 3,7,10,14 and 21 days after operation (T0-5).Results Compared with group S,MWT was significantly decreased and TWL was shortened at T2-5 in NP and T groups.Compared with group NP,MWT was significantly increased and TWL was prolonged at T3,4 in group T.Conclusion Histone deacetylase in the spinal cord is involved in the maintenance of neuropathic pain in rats.
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Objective To study the structural features and anticoagulant activity of the polysaccharide isolated from Aeodes orbitosa.Methods Sugar composition analysis,methylation analysis and IR were used to characterize the structural features.The anticoagulant activity of the polysaccharide was evaluated by cutting tail and capillary methods.Results The polysaccharide was composed of 3,6-anhydrous-galactose,6-methyl-galactose,2-methyl-galactose,galactose,xylose and glucose in the molar ratios of 6.4∶0.9∶5.8∶1.6∶84.1∶1.2.The content of Sulfate group was 37.5%. The main linkage model of the polysaccharide were 1,3 and 1,4 linkages,branch point located at O-2 and 6 of galactose residues.Sulfate group located at 2 and 6 position of 1,4 linked galactose residue and 2 position of 1,3 linked galactose residue.The polysaccharide showed significant activities to extend bleeding time and coagulation time in mice.Conclusion The polysaccharide from Aeodes orbitosa was a sulfate galactan with strong anticoagulant activity.