| Background: Pain is an unpleasant sensory and emotional experience related to actual or potential tissue injury.The World Health Organization lists pain as the "fifth sign" after body temperature,respiration,pulse and blood pressure,and about 50% of people in China suffer from chronic pain to varying degrees.Inflammatory pain is a common type of chronic pain,and its pathological mechanism is complex,which seriously affects the physical and mental health of patients.Therefore,it is of great significance to explore the mechanism of inflammatory pain and find new drugs to treat inflammatory pain to improve the health of patients.Related studies have shown that baicalein and baicalin,the effective components in ethanol extract of Scutellaria baicalensis Georgi(SGE),have analgesic effects,but the effect of SGE on relieving inflammatory pain has not been reported.P2X3(purinergic receptor P2X3)has been proved to be a key target for regulation of pain signals,which are related to various types of pain.The purpose of this study is to explore the therapeutic effect of SGE on inflammatory pain and its mechanism on P2X3 inhibition,so as to provide reference for the treatment of inflammatory pain.Objective: To clarify the relieving effect of SGE on inflammatory pain.To reveal the molecular mechanism of SGE in improving inflammatory pain by acting on P2X3 receptor.Methods: 1.The rat model of inflammatory pain was induced by CFA,and the changes of mechanical pain threshold,thermal pain threshold and motor coordination ability of inflammatory pain rats were measured by von Frey hair,electronic tenderness instrument,thermal stimulator system,hot plate and rotating rod experiment,so as to evaluate the effects of SGE on the behavior of inflammatory pain rats.HE staining and Nissl staining were used to evaluate the improvement effects of SGE on pathological injury in rats with inflammatory pain.2.The levels of inflammatory factors interleukin-1β(IL-1β),interleukin-6(IL-6)and tumor necrosis factor α(TNF-α)were detected by ELISA experiment,and the expression of P2X3 receptor was detected by immunofluorescence experiment.The protein expressions of inflammatory protein P2X3,nuclear factor kappa-b(NF-κB),p-NF-κB and cyclooxygenase-2(COX-2)were detected by Western blot,and the mechanisms of SGE in improving CFA-induced pain by inhibiting inflammatory reaction was explored.3.The P2X3 receptor agonist was added to CFA-induced inflammatory pain rat model,to verify the effects of SGE on regulation of P2X3/NF-κB/ERK1/2 signal pathway by acting on P2X3 receptor.The changes of inflammatory factors(IL-1β,IL-6,TNF-α)were detected by ELISA.The changes of P2X3 receptor expression after adding agonist were detected by immunofluorescence.Western blot was used to detect the protein levels of P2X3,NF-κB,p-NF-κB,ERK1/2,p-ERK1/2 and COX-2.q RT-PCR experiment was used to detect the gene expression changes of P2X3,NF-κB,COX-2,IL-1β,IL-6 and TNF-α.The mechanisms of SGE in inhibiting inflammatory pain by acting on P2X3 receptor was verified.Results: 1.Behavioral results showed that obvious behavioral abnormalities were observed in rats induced by CFA for one week.SGE(3 g/kg,6 g/kg)can significantly increase the mechanical pain threshold and thermal pain threshold of rats with inflammatory pain after 4 weeks of administration,and SGE(6 g/kg)can significantly improve the motor coordination ability of rats with inflammatory pain and prolong the retention time of rats on the rotating rod.HE staining and Nissl staining showed that SGE could significantly improve the pathological damage of dorsal root ganglion in CFA-induced inflammatory pain rats.2.ELISA results showed that SGE could significantly reduce the secretion of IL-1β,IL-6 and TNF-α.Immunofluorescence experiment showed that the SGE could significantly down-regulate the expression of P2X3 receptor.Western blot experiment showed that the SGE inhibited the expression of P2X3,NF-κB,p-NF-κB and COX-2.3.P2X3 receptor agonist(α,β me-ATP)can further aggravate the inflammatory pain induced by CFA in rats,while SGE can significantly increase the pain threshold and alleviate the inflammatory pain.SGE can alleviate pathological injury,inhibit the expression of P2X3 and inhibit the increase of inflammatory factors caused by α,β me-ATP.SGE can also inhibit the activation of NF-κB and ERK1/2 induced by α,β me-ATP,and inhibit the m RNA expression of P2X3,COX-2,NF-κB,IL-1β,IL-6 and TNF-α in dorsal root ganglion of rats induced by CFA combined with α,β me-ATP.Conclusion: SGE can alleviate CFA-induced inflammatory pain behaviors in rats,and its mechanisms may be related to the inhibition of P2X3 receptor. |
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