Abstract: Objective To investigate the effect and mechanism of Thymosin beta4(Tβ4) on angiogenesis in rat cerebral cortex after focal cerebral ischemia/reperfusion. Methods Rats were randomly divided into sham group(S), model group(IR), Tβ4 group(IRT), Tβ4+LY294002 group(IRTL), 0.9% sodium chloride injection group(IRN). The focal ischemia/reperfusion rat model was established by filament occluding the right middle cerebral artery for 2 hours. Rats were divided into 3 and 7 day subgroups in IR、IRN and IRT group. The protein expression of eNOS、p-Akt and Akt were detected by western blotting. Immunohistochemical method was selected to detect the expression of Tβ4 and CD31. The mRNA expression of eNOS、SDF-1 and CXCR4 were tested by fluorogenic quantitative PCR. Longa score was selected to evaluate neurobehavioral. Results Compare with IRN group, the protein expression of Tβ4 increased significantly at IRT 3 day(P<0.01); compared with IRN group, the protein expression of eNOS、p-Akt increased significantly at IRT 3 and 7 day (p<0.05), but in IRTL group they reduced significantly (P<0.01); compare with IRN group , the mRNA expression of eNOS、SDF-1 and CXCR4 were increased significantly at IRT 3 and 7 day (p<0.05); The number of CD31 postive micrangium increased significantly at IRT 3 and 7 day (P<0.05) and the neural function recovery significantly at IRT 7 day (p<0.05). Conclusion Tβ4 may promotes angiogenesis and behavioral recovery by increasing p-Akt and eNOS expression in a rat model of focal cerebral ischemia/reperfusion.

Key words: Thymosinβ4, focal cerebral ischemia/reperfusion, angiogenesis, eNOS, CD31, SDF-1/CXCR4, PI3K/Akt