| Objective:This study based on intervention of Shaoyao Gancao Decoction to rat model of cervical spondylotic radiculopathy in the acute phase,we observed some indicators to explore the possible treatment mechanisms of Shaoyao Gancao Decoction.Indicators included morphological changes of the cervical spinal cord tissue,the activation of microglia in the anterior horn of the cervical spinal cord and the expression of NLRP3 inflammasome,etc.Methods:Male Sprague-Dawley rats were divided into sham group(n=12)and operation group.Model rats of the operation group were prepared by inserting a nylon fishing line into the cervical spinal canal,then the rats were evaluated by animals’ general situation,BBB rating scale and MRI to comprehensively evaluate whether the model was successful.After rat model been successfully set up,model rats were randomly divided into four groups: model group,Shaoyao Gancao Decoction high,medium and low dose group,12 rats in each group.According to the dose,rats in each group were intragastrically administered with Shaoyao Gancao Decoction.The perfusion dose was 2ml,rats were intragastrically administered twice a day for 7 days.Model and sham group were intragastrically administered with the same volume and frequency of saline.Rats in each group were given free access to water and food during the experiment.After 7 days of intervention,whole blood was collected from the abdominal aorta of rats one hour later than the last gavage,blood samples were used to detect inflammatory factors such as IL-33,IL-18,TNF-α,etc.Rats were sacrificed after blood collection and divided into two groups by random number table method,spinal cord tissue specimens were collected in each group and preserved for protein and histomorphology test,etc.Results:1.General condition of model rats,rats had inconvenient movements,and activity range of the left limb was significantly smaller than the right,and the right limb was mainly used forfeeding and grasping while the left limb often curled up or placed on the chest,etc.Falling hair,weight loss in rat models observed too.2.MRI results of each group showed local edema of the nerve roots after operation.After7 days of intervention,edema volume of the drug group reduced significantly compared with that of the model group,indicating that the intervention of Shaoyao Gancao Decoction can alleviate local inflammatory edema.3.BBB rating scale were used to evaluate postoperative and post-intervention conditions of rats in each group.Scores of model rats were significantly decreased,and the difference was statistically significant(P<0.05).After intervention,scores of the intervention group and the model group were compared,and the difference were statistically significant(P<0.05);and scores’ difference between high-dose and low-dose group was statistically significant(P<0.05).This indicates that the intervention of Shaoyao Gancao Decoction could help function recovery in model rats,and its therapeutic effect depends on time and dosage.4.Morphological comparison,HE and Nissl staining of cervical spinal cord tissue:Compared with the sham group,the anterior horn of the cervical spinal cord in the model group and the high,middle and low dose group showed different degrees of inflammation,the model group was severer than that of the intervention group which indicates that Shaoyao Gancao Decoction could alleviate local nerve tissue damage.5.Comparison of plasma inflammatory factors IL-33,IL-18,TNF-α expression levels:The inflammatory factor levels in the model group were statistically higher than those in the sham group(P<0.001).After drug intervention,levels of inflammatory factors in each dose group were lower than those in the model group,and the differences was statistically significant(P<0.05).This indicates that the level of inflammatory factors in rats increased,and the intervention of Shaoyao Gancao Decoction could decrease the expression of related inflammatory factors.6.Comparison of NLRP3 inflammasome expression in local spinal cord tissue: after the intervention of Shaoyao Gancao Decoction,the expression levels of NLRP3 inflammasome protein in different dose group were statistically different.The value of middle and high dose group <low dose group<model group.After drug intervention,expression levels of NLRP3 protein showed a downward trend compared with the model group,and levels of the middleand high dose group were lower than that of the low dose group which indicates that specific dosage has a stronger anti-inflammation effect.Conclusion:1.Shaoyao Gancao Decoction has a therapeutic effect on acute cervical spondylotic radiculopathy by alleviating local inflammatory damage,and its effect is dose and time dependent,the middle and high dose group are more effective than the low dose group after various indicators been compared and analyzed while difference between the medium and high dose group isn’t significant.2.Shaoyao Gancao Decoction could inhibit synthesis and release of NLRP3 inflammasome in the spinal cord and decrease levels of related inflammatory factors such as IL33,IL-18,TNF-α,etc.This could be one of the mechanisms by which Shaoyao Gancao Decoction cures acute cervical radiculopathy in rats. |
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