Salvianolic Acid B Inhibition Of Cerebral Ischemia And Reperfusion Inflammatory Response Mechanism

Cerebrovascular disease called"stroke"by Chinese traditional medicine,is one of the obstinate,high-disabled and high-relapsed disease.It threats the health of humankind,especially aged people.Epidemiological survey data has suggested that in the incidence of cerebrovascular disease,ischemic cerebrovascular disease accounted for 60%to 80%.The patients are treated by methods of thrombolysis,but induce to reperfusion injure.Ischemia-reperfusion was due to overloading of intracellular Ca²⁺,active oxygen,excitatory amino acid neurotoxicity,NO cytotoxic,inflammatory response,apoptosis,and so on.Those factors react for each other and lead to the nerve injury and death eventually.More reseaches have focused on the mechanisms of inflammatory response.The ischemic stroke in theory of chinese medicine is considered that wind,fire, expectoration and stasis caused by disorder of qi and blood,induce obliteration of brain collaterals.The characteristic of pathogenesis is deficiency of vital energy and blood stasis, blockage of expectoration and stasis,injury of brain collaterals because of toxin,disorder of activities of qi and emphraxis of the upper orifices.The method of activating blood flow and removing blood stasis has been identificated in the treatment for ischemic stroke.Pharmacology researches have demonstrated that the herbs of activating blood flow and removing blood stasis could vasodilatate,increase circulation volume,suppress blood platelet coacervation and protect brain tissue.Salvia miltiorrhiza,an herb which can activate blood circulation to dissipate blood stasis,is applied to the treatment of blood vessel disease extensively nowdays.Salvianolic acid B (SalB),a main water soluble composition of salvia miltiorrhiza,is the condensation of three molecule danshensu and one molecule caffeic acid.A large amount of studies have already proved that SalB could protect ischemia-reperfusion from injury,which may be related with its resisting lipid peroxidation,removing free radical,improving the blood flow and energy metabolism of brain,sustaining normal function of vascular endothelial cell and decreasing the number of neuron apoptosis.As a result,it is important that exploring mechanisms of SalB effecting on ischemic cerebrovascular disease supports treatment in clinic.Objective:In order to explore the effect of salvianolic acid B(SalB) on inflammatory response in mice with cerebral ischemia-reperfusion injury.Methods: NIH mice were randomLy divided into four groups:sham-operated group,model group, SalB group and Nimdipine(Nim) group.Model group:Sodium Chloride(5 mL/kg) was injected into vena caudalis of NIH mice.After 30 min,mice were anesthetized with Chloral Hydrate by intraperitoneal injection.Then center of neck was cut open and double arteria carotis communis were exposed.Nitroprusside sodium(2.25 mg/kg) was injected into abdominal cavity of NIH mice.At the same time,double arteria carotis communis were occlused for 30 min, then unclamped bulldog clamp to reperfuse for 6h,12h.Sham-operated group:duplication of model was the same as model group,but nitroprusside sodium was not injected and double arteria carotis communis were not occlused.Nim group and SalB group:Nim(1 mg/kg) and SalB (22.5 mg/kg) were injected into vena caudalis of NIH mice respectively.Duplication of model was also the same as model group.Experiment index were detected by blood plasma and brain tissue at 6 h and 12 h after brain ischemia-reperfusion.The conent of tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),water content of brain,brain index,the content of TXB₂ and 6-keto-PGF1_αwere measured,pathomorphology changes in cortex were observed,the protein expression of intercellular adhesion molecule-1(ICAM-1) and P-selectin in cortex were investigated.Results:1.The effect of SalB on content of water in brain tissue and cerebral index in mice with brain ischemia-reperfusionThe contents of water in brain tissue and cerebral had an increase tendency with reperfusion time lasting,and there was a significant different compared with sham-operated group(P＜0.01). SalB and Nim reduced content of water in brain tissue and cerebral index,especially at 12h after brain ischemia-reperfusion,it made a noticeable contrast with model group(P＜0.01)2.The effect of SalB on pathomorphology changes in mice with cerebral ischemia-reperfusion.The results showed that morphology structure of neuron was normal and vascular endothelial cell connect closely.Matrix oedema was observed in model group at 6 h.At 12 h,the colour of neuron nucleus were stained deeply and vascular interspace increased markedly.SalB and Nim improved pathomorphology changes involving hydroncus and the number of neuron necrosis.3.The effect of SalB on TXB₂ and 6-keto-PGF1_αin blood plasma of mice with brain ischemia-reperfusionThe content of TXB₂ increased evidently at 6 h and 12 h in the model group(P＜0.01),the content of 6-keto-PGF1_αhad a decrease tendency,and TXB₂/6-keto-PGF1_αratio increased markedly(P＜0.01).SalB and Nim could decreased the content of TXB₂ and SalB had a different significantly compared with model group(P＜0.01).At 6 h,the content of 6-keto-PGF1_αdeseased in Nim group(P＜0.05) and TXB₂/6-keto-PGF1_αratio decreased in the two groups(P＜0.01).4.The effect of SalB on IL-1β,TNF-αin brain tissue of mice with brain ischemia-reperfusionCompared with sham-operated group,the content of IL-1βand TNF-αincreased in brain tissue at different time of brain ischemia-reperfusion(P＜0.01 or P＜0.05 ).SalB decreased the content of IL-1βand TNF-α,and the content of IL-1βdecreased significantly(P＜0.01).The content of TNF-αdecreased in Nim group at 6 h(P＜0.01).5.The effect of SalB on ICAM-1,P-selectin in brain cortex in mice with brain ischemia-reperfusionIn sham-operated group the expression of ICAM-1,P-selectin in blood vessels of brain cortex were observed rarely,but in model group the expression of ICAM-1,P-selectin in blood vessels were observed clearly.They were located at capillary endothelium,stained by buffy color in vessel walls.The mean optical densities were significantly increased.SalB and Nim decreased the expression of ICAM-1 compared with model group at different time(P＜0.01).The expression of P-selectin decreased at 12 h significantly compared with model group(P＜0.01).Conclusion:SalB reduces brain edema and inhibits inflammation,which may contribute to its effort on reducing the content of TXB₂ and TXB₂/6-keto-PGF1_αratio,the content of IL-1βand TNF-α,and expression of ICAM-1,P-selectin.