Background and aims: Adrenomedullin (AM) is a peptide hormone widely distributed in the central nervous system. AM has been shown induced angiogenesis and inhibits cell apoptosis through the phosphatidylinositol 3-kinase/Akt pathway. The purpose of this study is evaluation of the effects of intra-ventricular AM on the photochemical thrombotic ischemic cortical injury. Method: Male Sprague-Dawley rats were assigned to eight groups and cortical photothrombosis was induced in the sensorimotor cortex. Micro-injector contained either 0.9% saline or rat AM (SIGMA), that continuous infused into ipsilateral ventricle 2 h after operation (released rate, 1.0 ug/kg/min (0.5nmol)). The effects of AM on neuro-protection, angiogenesis and apoptosis were analyzed by immunohistochemical study. The pathophysiologic mechanisms of AM on stroke were evaluated by p-JNK1/2, p-ERK1/2 and p-Akt. Results: AM increased NeuN positive cells and RECA-1 staining in sham operation and stroke groups at 12 h and 24 h. There is slightly decreased of TUNEL-positive cells in AM treatment groups at 12 h but significantly decreased at 24 h .The activations of JNK1/2, Erk1/2 and Akt were increased by AM at 12h and 24 h. Conclusion: We found that AM promote neuro-protection, angiogenesis and anti-apoptosis after ischemic injury, possibly through activation of JNK1/2, ERK1/2 and Akt pathways. Our results suggest that AM may be benefited for the treatment of cerebral ischemia.
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