Abstract: Objective To study the protective effect and mechanism of edaravone dexborneol on acute cerebral infarction after intravenous thrombolysis. 
Methods As a prospective observational study, this study included 95 cases undergoing intravenous thrombolysis with alteplase(rtPA). All patients were divided into rtPA group(n=40), and rtPA+edaravone dexborneol group(n=55) according to different treatment regimens. The primary end point events were National Institute of Health Stroke Scale(NIHSS) score at 14 d after onset, the percentage of patients with a modified Rankin Scale Score(mRS)≤1 at 90 d after onset, and the incidence of symptomatic intracranial hemorrhage(sICH) within 36 h after treatment. Secondary indicators included serum of the two groups collected at admission and at 14 d after admission, and the levels of superoxide dismutase(SOD), interleukin-6(IL-6), tumor necrosis factor-α(TNF-α)and matrix metalloproteinase-9(MMP-9). The number and total proportion of CD4-negative T-lymphocytes(CD4-T)+CD8-negative T-lymphocytes(CD8-T) were analyzed using flow cytometry analysis.The relationship between time of using edaravone dexborneol, NIHSS score at admission, Trial of Org10172 in Acute Stroke Treatment(TOAST)and endpoint events in edaravone dexborneol group was analyzed. 
Results There was no significant difference in improvement rate of NIHSS score between two groups at 14 d(P＞0.05), and the proportion of mRS ≤ 1 at 90 d was 45% and 67% respectively, which was higher in rtPA+Edaravone Dexborneol group(P＜0.05). After treatment, the levels of SOD, IL-6, TNF-α and MMP-9 in both groups were lower than those before treatment, while the levels of SOD, IL-6, TNF-α and MMP-9 in rtPA+edaravone dexborneol group were lower than those in rtPA group(P＜0.05). After treatment, the count and proportion of CD4-T+CD8-T in the serum of the two groups were lower than those before treatment, which were lower in the intravenous thrombolysis+edaravone dexborneol group than in the intravenous thrombolysis group(P＜0.05). Logistic regression analysis showed that the endpoint events were correlated with the NIHSS score at admission and the time to initiate edaravone dexborneol(P＜0.05). 
Conclusion Edaravone dexborneol can ameliorate ischemia-reperfusion injury after intravenous thrombolysis for acute cerebral infarction. The mechanism may be related to scavenge of oxygen free radicals, anti-inflammation, protection of blood-brain barrier and regulation of immunity.

Key words: brain infarction, intravenous thrombolysis, Edaravone Dexborneol