Anti-inflammatory effect of neuregulin on cerebral ischemic reperfusion injury in rats and its mechanism

Objective To study the inhibitive effects of neuregulin-1β(NRG-1β) on neuronal apoptosis and inflammatory responses after cerebral ischemic reperfusion injury in rats and its mechanism.Methods Middle cerebral artery occlusion reperfusion(MCAO/R) models were established by intraluminal thread methods in rats.Neuregulin-1β(2μg /kg) was injected into the internal carotid artery for treatment.The cerebral infarction volume was revealed by tetrazolium chloride(TTC) stain,the apoptosis positive cells were counted by immunofluorescence assay,and the expression of tyrosine kinase receptor(ErbB-4) and matrix metalloproteinase-9(MMP-9) in gliocytes were determined by immunohistochemical assay.Results The number of neuronal apoptosis cells increased significantly and the expression of ErbB-4 and MMP-9 in gliocytes was highly enhanced after ischemic reperfusion injury.After treated with NRG-1β,the cerebral infarction volume and the number of neuronal apoptotic cells were reduced significantly.ErbB-4 receptors were over-expressed while the MMP-9 was down-regulated(P0.05).Conclusion NRG-1β may play an anti-inflammatory effect by down-regulating the expression of MMP-9 in gliocyte and inhibiting the neuronal apoptosis induced by ischemia reperfusion injury.