| Objective:The experimental study was conducted to observe the effects of Jiaji electroacupuncture on motor function and histomorphology in rats with spinal cord injury.Using IL-18 as an entry point,BBB scoring,HE staining and IHC method were used to explore the therapeutic mechanism of the inflammatory response after spinal cord injury from different levels.Method: The experiment was divided into two parts.Experiment 1: Effects of Jiaji electroacupuncture on behavior and histomorphology of SCI ratsThirty adult female SD rats were randomly divided into five groups:Sham group,Model group,Jiaji electroacupuncture group(EA group),NLRP3 agonist group(MSU group),NLRP3 agonist + Jiaji electroacupuncture group(MSU + EA group),six rats in each group.Sham group: sutured immediately after exposure of spinal cord tissue,without any treatment;Model group:regular feeding after successful modeling,without any treatment;MSU group:200μ g/ml/kg MSU was injected intraperitoneally into the rats 5min,6h and24 h after the model preparation;MSU+EA group: 200 μ g/ml/kg MSU was injected intraperitoneally into the rats 5min,6h and 24 h after the model preparation.The rats were injected with 200μg/ml/kg MSU intraperitoneally and treated with Jiaji electroacupuncture(MSU is monosodium urate,which can promote the activation of NLRP3 inflammatory vesicles)at 5min,6h and24 h after the model preparation.After moulding,each group was randomly divided into two subgroups according to the 3 d and 7 d time points,and the indexes were tested separately.Experiment 2: Effects of Jiaji electroacupuncture on IL-18 Protein Expression in SCI Rats by IHCThirty SD adult female rats were randomly divided into sham-operated group(Sham group),Model group(Model group),Jiaji electroacupuncture group(EA group),NLRP3 agonist group(MSU group),NLRP3 agonist+ Jiaji electroacupuncture group(MSU+EA group),six rats in each group,and the model preparation and intervention methods were the same as in Experiment 1.Results:1.BBB score results:The BBB scores of the rats in the Sham group were21 at the time points of 3 d and 7 d postoperatively,with no statistically significant difference.Compared with the Sham group,the BBB scores of the rats in the Model,MSU,EA and MSU+EA groups were significantly lower than those in the Sham group,showing a statistically significant difference(P<0.05)in terms of successful modelling.Compared with the Model group,the BBB scores of rats in the EA group were significantly higher,and the difference was statistically significant(P<0.05).Compared with the MSU group,the rats in the MSU+EA group had improved limb mobility and higher BBB scores after electro-acupuncture treatment by clamping the spine,and the difference was statistically significant(P<0.05).2.HE staining results: Except for the Sham group,the spinal cord tissues of the other four groups showed different degrees of structural damage.The spinal cord cells in the Sham group were morphologically intact,arranged in an orderly manner,with clear boundaries to the surrounding tissues,no swelling or tissue degeneration in the cytosol,rounded and clearly visible nuclei,and no haemorrhage or cell infiltration.At 3 d after surgery,the spinal cord tissues of the Model group were congested with loosely arranged cells,infiltrated by inflammatory cells,with a small amount of neuronal loss,a slight wrinkling of the nucleus pulposus,and a smaller cell body;The morphological changes of the spinal cord cells in the MSU+EA group were similar to those in the Model group,with congestion and inflammatory cell infiltration,and wrinkled nuclei.At 7 d after surgery,the spinal cord tissue of the MSU group was severely loosened,a large number of vacuoles were formed,the number of neurons was further reduced,and the nuclei of the cells were severely wrinkled and smaller.The intracellular congestion was reduced,the inflammatory cells were further reduced,the boundary between the grey and white matter of the spinal cord was faintly visible,the intracellular vacuoles were reduced,and the morphology of the neurons was normalized.3.IHC test results:At the time points of 3d and 7d postoperatively,IL-18protein-positive cells in the spinal cord tissues of rats in the Sham group showed low expression,and the differences were not statistically significant.Compared with the Sham group,the mean optical density of IL-18 positive cells in the spinal cord tissues of the Model,MSU,EA and MSU+EA groups at 3 d and 7 d postoperatively was significantly higher,and the difference was statistically significant(P<0.05),indicating that the model was successfully prepared.Compared with the Model group,the mean optical density of IL-18protein-positive cells in the spinal cord tissues of rats in the EA group was significantly lower,and the difference was statistically significant(P<0.05);compared with the MSU group,the mean optical density of IL-18protein-positive cells in the spinal cord tissues of rats in the MSU+EA group was significantly lower,and the difference was statistically significant(P<0.05).The mean optical density of IL-18 protein-positive cells was significantly higher in the MSU group compared with the Model group(P<0.05).Conclusion:1.Jiaji electroacupuncture promotes the recovery of motor function in the hind limbs of rats and attenuates the damage to rat spinal cord tissue caused by the inflammatory response after SCI;2.The mechanism of action of Jiaji electroacupuncture in regulating the inflammatory response in rats with SCI may be exerted by inhibiting the expression of IL-18 through regulating the activation of NLRP3 inflammatory vesicles. |
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