一氧化氮在休克大鼠离体淋巴管对P物质反应性中的作用

Role of nitric oxide in reactivity of isolated lymphatics to substance P in shock rats

目的:应用离体淋巴管灌流技术,观察一氧化氮(NO)在失血性休克(HS)大鼠离体淋巴管对P物质(SP)反应性双相变化中的作用。方法:Wistar雄性大鼠随机分为对照组(仅手术)和休克组(复制HS模型后分为shock 0.5 h、shock 2 h组)。在相应时点分离胸导管,制备淋巴管条,3 cmH2O跨壁压下行离体灌流,应用一氧化氮合酶(NOS)工具药分别孵育shock 0.5 h和shock 2 h的淋巴管。分别给予从低到高浓度的SP,测量淋巴管收缩末期口径、舒张末期口径、收缩频率(CF)和被动管径,计算收缩幅度(CA)、泵流分数(FPF)和紧张指数(TI),以给予SP前后淋巴管的CF、TI、CA和FPF的差值ΔCF、ΔTI、ΔCA和ΔFPF评价淋巴管对SP的反应性。结果:NO供体L-Arg可显著降低shock 0.5 h淋巴管对多个SP浓度点的ΔCF、ΔTI与ΔFPF;可溶性鸟苷酸环化酶抑制剂ODQ可显著抑制L-Arg的作用,在某些SP浓度点上,使ΔCF、ΔTI和ΔFPF显著高于shock 0.5 h+L-Arg组,ΔCF和ΔFPF高于对照组水平。NOS抑制剂L-NAME可提高shock 2 h淋巴管对多个SP浓度点的ΔCF、ΔTI与ΔFPF,且高于对照组水平;shock 2 h淋巴管与L-NAME和磷酸二酯酶抑制剂氨茶碱(AP)同时孵育后,在SP为1×10-8mol/L和3×10-8mol/L时,AP显著抑制了L-NAME的作用,使ΔCF、ΔTI与ΔFPF明显降低。结论:NO参与了休克淋巴管反应性的双相调节,其机制可能是通过环鸟苷酸实现的。

AIM： To observe the role of nitric oxide（NO） in the reactivity of isolated lymphatics to substance P（SP）,which presents a biphasic change,in the hemorrhagic shock（HS） rats with the technique of lymphatic perfusion in vitro.METHODS： Male Wistar rats were randomly divided into control group（surgical procedure only） and shock group（the rats were further divided into shock 0.5 h and shock 2 h groups after the HS model was established）.A segment of lymphatics was pressed and perfused in vitro at transmural pressure of 3 cmH2O after thoracic ducts were separated from the rats at the corresponding time points in each group.The lymphatics of shock 0.5 h and shock 2 h were incubated with different drugs for changing the activity of No and nitric oxide synthase（NOS）,respectively.The end-systolic diameter,end-diastolic diameter,contraction frequency（CF） and passive diameter of isolated lymphatics were measured,while the contraction amplitude（CA）,tonic index（TI） and fractional pump flow（FPF） were calculated after stimulated with gradient SP.Different values between pre-and post-administration of SP in CF,CA,TI and FPF were calculated and expressed as ΔCF,ΔTI,ΔCA and ΔFPF for further assessing the reactivity of lymphatics.RESULTS： NO donor L-Arg reduced ΔCF,ΔTI and ΔFPF of 0.5 h-shocked lymphatics treated with different concentrations of SP.The effect of L-Arg was obviously suppressed by a soluble guanylate cyclase inhibitor ODQ.ΔCF,ΔTI and ΔFPF increased strikingly compared with shock 0.5 h＋L-Arg group in the presence of SP at certain concentration,and ΔCF and ΔFPF increased remarkably compared with control group.NOS inhibitor L-NAME elevated ΔCF,ΔTI and ΔFPF of 2 h-shocked lymphatics treated with different concentrations of SP and the manifestation of lymphatics exceeded the values of control levels.In the experiment of 2 h-shocked lymphatics treated with L-NAME＋phosphodiesterase inhibitor aminophylline（AP）,the effect of L-NAME was suppressed significantly,which manifested by the decrease in ΔCF,ΔTI and ΔFPF as compared with the values of shock 2 h＋L-NAME group in the presence of SP at the concentrations of 1×10-8 mol/L and 3×10-8 mol/L.CONCLUSION： These data indicate that NO involves in the biphasic modulation of shocked lymphatics and the effect might be involved in the action of cyclic guanosine monophosphate.