RESUMO
ObjectiveTo clarify the intervention effect of Osteoking （OK） in rats with myofascial pain syndrome （MPS） and preliminarily explore the pharmacological mechanism of OK in relieving chronic pain from the perspective of anti-inflammatory disease. MethodThe 60 SD rats were divided into normal group， model group， low， medium， and high dose OK groups （0.66， 1.31， 2.63 mL·kg-1）， and positive celecoxib group （21 mg·kg-1）. The MPS rat model was established by beating combined with the centrifugal exercise method， and the OK and celecoxib were given at the same time. SMALGO paw pressure pain manometer detected the shock pain point tenderness threshold of rats， and the Von-Frey needle and acetone stimulation method detected the mechanical hyperalgesia threshold and cold hyperalgesia stimulation response respectively. Eight weeks and 10 weeks after modeling， the spontaneous discharge state and convulsion response of MPS rats were determined by electromyograph （EMG） instrument. The gait changes of MPS rats were detected using a CatWalk gait analyzer. The expression levels of interleukin-1 β （IL-1β）， tumor necrosis factor-α （TNF-α）， substance P （SP）， and bradykinin （BK） were measured by enzyme-linked immunosorbent assay （ELISA）. The protein expression levels of nuclear transcription factor-κB （NF-κB） inhibiting protein α （IκBα）， phosphorylates （p）- IκBα， NF-κB p65， and p-NF-κB p65 were detected in MPS rats by Western blot. The positive expression of p-NF-κB p65 was detected by immunofluorescence. ResultCompared with the normal group， the model group shows 100% positive rates for EMG signal and local convulsions response at both the 8th and 10th weeks. The tenderness threshold and mechanical hyperalgesia threshold are significantly reduced. Cold hyperalgesia score is significantly increased， and gait is abnormal. The expression levels of serum and trigger points IL-1β， TNF-α， SP， BK， p-IκBα， and p-NF-κB p65， as well as the positive expression intensity of p-NF-κB p65 are significantly increased （P<0.01）. Compared with the model group， the positive rate of EMG detection and local convulsion response is significantly reduced in the medium and high dose OK groups （P<0.05）. The tenderness threshold and mechanical hyperalgesia threshold increase significantly in the medium and high dose OK groups， and the cold hyperalgesia score is significantly reduced in the high dose OK group （P<0.01）. The standing time， swing time， and walking period are significantly increased. The swing speed， maximum contact area， and maximum contact intensity are significantly decreased in the high dose OK group （P<0.05）. Moreover， the protein expression levels of p-IκBα/IκBα and p-NF-κB p65/NF-κB p65 are significantly reduced in the medium and high dose OK groups （P<0.05，P<0.01）. The positive expression intensity of p-NF-κB p65 is significantly decreased in the high dose OK group （P<0.01）. ConclusionThe mechanism of OK in relieving the pain in trigger points of MPS and improving gait abnormalities is related to the downregulation of the NF-κB p65 inflammatory signaling pathway to reduce the expression of inflammatory factors and pain mediators in blood and trigger point tissue.