蜂毒镇痛作用的昼夜变化及对外周血P物质β-内啡肽和IL-1β水平的影响

Circadian Rhythm of Pain Threshold in Mouse Model and the Analgesic Effect of Bee Venom for Injection:Correlation with Peripheral Blood Substance Pβ-Endorphin and IL-1βLevels

目的:探讨小鼠疼痛模型的昼夜节律和注射用蜂毒(Bee venom for injection,BVI)镇痛作用的昼夜差异及其相关机制。方法:采用热板法、辐射热甩尾法建立小鼠疼痛模型,在6个授时(Zeitgeber time,ZT)时间点(ZT2、ZT6、ZT10、ZT14、ZT18、ZT22)测量痛阈并分析其昼夜节律。将合格昆明小鼠随机分为注射用蜂毒大剂量(Bee venom for injection-High dose,BVI-H)、注射用蜂毒中剂量(Bee venom for injection-Medium dose,BVI-M)、注射用蜂毒低剂量(Bee venom for injection-low dose,BVI-L)、吗啡(Morphine,MOR)和模型(Model,MOD)组;每组再根据小鼠痛阈的昼夜节律分为两个亚组,分别在痛阈的峰值和谷值2个时间点给药。观察各组对热板法、辐射热甩尾法和扭体法疼痛模型小鼠行为学影响的动态变化;ELISA法检测血清P物质(Substances P,SP)、β-内啡肽(Beta-endorphin,β-EP)和IL-1β(interleukin-1β,IL-1β)水平。结果:小鼠疼痛模型的痛阈显示出峰值在明中期(ZT6)、谷值在暗后期(ZT22)的昼夜节律。BVI三个剂量组和MOR组均显示出明显的镇痛作用,并且BVI在热板法和扭体法模型的镇痛作用具有剂量依赖性。在热板法和辐射热法疼痛模型中,BVI于ZT22给药比ZT6给药显示出更强的镇痛作用。蜂毒对疼痛模型小鼠血清β-EP水平未显示上调作用;但可明显降低血清SP含量,且具有ZT22给药低于ZT6给药的昼夜变化(P<0.05);对扭体法和辐射热法(仅ZT22给药组)疼痛模型小鼠血清IL-1β水平显著下调,而在热板法则显示IL-1β水平明显增高。结论:小鼠的痛阈存在峰值在明中后期、谷值在暗后期的昼夜节律;BVI对小鼠多种疼痛模型均具有镇痛作用,且存在昼夜差异;BVI的镇痛作用及其昼夜变化可能与调节内源性疼痛介质有关。

Objective:To investigate the circadian rhythm of pain threshold in mouse models and the circadian difference in the analgesic effects of bee venom for injection(BVI)and its mechanisms.Methods:Mouse pain models were established using the hot plate test and radiant heat tail-flick test.Pain thresholds were measured at six zeitgeber time(ZT)points(ZT2,ZT6,ZT10,ZT14,ZT18,ZT22)to analyze their circadian rhythms.Qualified Kunming mice were randomly divided into Bee Venom for Injection high dose(BVI-H),Bee Venom for Injection medium dose(BVI-M),Bee Venom for Injection low dose(BVI-L),Morphine(MOR),and Model(MOD)groups.Each group was further divided into two subgroups based on the circadian rhythm of pain thresholds,and drugs were administered at two time points corresponding to the peak and trough of pain thresholds.The dynamic changes in the behavioral effects on pain models in mice were observed using the hot plate test,radiant heat tail-flick test,and writhing test.The levels of serum Substances P(SP),Beta-endorphin(β-EP),and interleukin-1β(IL-1β)were measured by ELISA.Results:The pain thresholds of the mouse pain model exhibited circadian rhythms with a peak in the mid-light phase(ZT6)and a trough in the late dark phase(ZT22).The three BVI dose groups and the MOR group all showed significant analgesic effects,and the analgesic effect of BVI in the hot plate and writhing models was dose-dependent.In the hot plate test and radiant heat test models,BVI administration at ZT22 showed stronger analgesic effects than at ZT6.Bee venom did not upregulate serumβ-EP levels in pain model mice but significantly reduced serum SP levels,with a circadian variation(lower at ZT22 than at ZT6,P<0.05).The serum IL-1βlevels were significantly downregulated in the writhing test and radiant heat test(ZT22 administration group only)pain model mice,while they were significantly increased in the hot plate test.Conclusion:The pain threshold in mice exhibits a circadian rhythm with a peak in the middle-late light phase and a trough value in the late dark phase.BVI has analgesic effect on various pain models in mice,and there is a diurnal difference.The analgesic effect of BVI and its diurnal variation may be related to the regulation of endogenous pain mediators.