Age-related changes in cerebral angiogenesis and fetal liver kinase-1 expression after cerebral ischemia/reperfusion

Cerebral angiogenesis in the early stages after cerebral ischemia injury is essential for the recovery of nerve function,in which fetal liver kinase-1（Flk-1）,as a major regulator of vasculogenesis and angiogenesis,plays a very important role.Microvessel density（MVD）was greater in an aged model group compared with the young sham operated group（P 〈 0.01）.MVD and the sum of the lumen area were decreased in the aged group at 1,3,6 and 12 days following ischemia/reperfusion（I/R）injury compared with the young model group（P 〈 0.05 and P 〈 0.01,respectively）.Flk-1 protein and mRNA expression was greater in the aged model group when compared with the young sham operated group（P 〈 0.01）.Flk-1 protein and mRNA expression was lower in the aged group at 1,3,6 and 12 days after I/R compared with the young model group（P 〈 0.01）.Flk-1 expression in aged rats attenuated rapidly,but was still maintained at relatively higher levels at 12 days following I/R in younger rats.The results suggest that angiogenesis was weakened after cerebral I/R in aged rats,and the mechanism of which might be correlated with attenuated expression of Flk-1 protein and mRNA.