Impact of DADLE on ERK signal transduction pathway in brain tissue in rats with acute global cerebral ischemia-reperfusion injury

Abstract

Objective To investigate the impact of DADLE on ERK signal transduction pathway in brain tissue in rats with acute global cerebral ischemia-reperfusion injury and the association of DADLE with cerebral protection.Methods Fifty female Sprague-Dawley rats (180-220 g) were randomly divided into 5 groups.Ischemia/reperfusion group (I/R,n =10) was induced by bilateral common artery occlusion combined with hypotension for 15-minute global ischemia followed by 120-minute reperfusion ; sham group (Sham,n =10) exposed bilateral common artery without occlusion; DADLE group was subdivided into DADLE of 2 mg/kg group (A,n =10),DADLE of 3 mg/kg group (B,n =10),and DADLE of 5 mg/kg group (C,n =10).DADLE was applied through external jugular vein before reperfusion.Neuropathological changes in hippocampus CAI area were detected by Hernatoxylin-Eosin (H-E) staining; and the expressions of ERK and phosphorylated ERK (p-ERK) in brain tissue were determined by Western blot.Pesults Expression levels of ERK and p-ERK were significantly lower in sham group than in I/R group and DADLE group (P＜0.05).And the expression levels of ERK and p-ERK were increased in DADLE group as compared with I/R group (P＜0.05).Among the DADLE subgroups,the expression levels of ERK and p-ERK were higher in groups B and C than in group A,but no statistical difference was found between group B and group C.Conclusions DADLE activates ERK signal transduction pathway in brain tissue in rats with acute global cerebral ischemia-reperfusion injury and reduce neuronal cell damage.Tthe neuroprotective action of DADLE is dose-related and has ‘ceiling effect'. Key words: DADLE; Global cerebral ischemia and reperfusion; ERK