Effects And Mechanisms Of DADLE On Focal Cerebral Ischemia-reperfusion Injury

Objective: To investigate the protective effects and preliminary underlying mechanisms of DADLE via intracerebroventricular injection on focal cerebral ischemia-reperfusion injury(IRI)in rats,and to investigate whether it provides protection through Toll-like receptor 4(TLR4)/nuclear factor kappaB(NF-?B)signaling pathway in the brain.Methods: Focal cerebral IRI was induced in SD rats by MCAO for 2 h.Then the animals were treated with DADLE 2.5 nmol dissolving in 5 ?L artificial cerebrospinal fluid(ACSF)or identical volume of ACSF via intracerebroventricular injection at 45 min after ischemia at a rate of 1.5 ?L/min.To explore the effects of DADLE and its protective mechanisms by examining TLR4 and the downstream NF-?B signaling pathway in a rat model of transient focal cerebral ischemia.The first part: investigation on neuroprotection.The experimental animals were randomly assigned into 3 groups: sham group,ACSF group and DADLE group.The rectal temperature was measured during experimental period.The neurological status,infarct volume and histopathological changes in the penumbral brain tissue were evaluated at 24 h after reperfusion.The survival rate of normal neurons was counted.The second part: investigation on protective mechanisms.Immunohistochemistry was used to analyse the expression of TLR4 in the ischemic penumbra.Western Blot and ELISA were used to detect the expression of TLR4,NF-?B p65,TNF-? and IL-6 in the ischemic penumbra.Results: Compared with the ACSF,DADLE significantly reduced neurological function,cerebral infarct size and neuronal damage.It also reduced the TLR4 positive cells and inhibited the expression of TLR4,NF-?B p65,TNF-? and IL-6 in the ischemic penumbra.Conclusion: DADLE 2.5 nmol by intracerebroventricular administration at 45 min after ischemia can attenuate focal cerebral IRI in rats.The neuroprotection might be due to down-regulation of inflammation through the TLR4/NF-?B signaling pathway.