Abstract:

Objective   To explore expression of matrix metalloproteinase-9 (MMP-9) and effect of neuregulin-1β (NRG-1β) on brain tissues of rats following cerebral ischemia/reperfusion.   Methods   Animal models of middle cerebral artery occlusion/reperfusion (MCAO/R) were established by a filament method in the left external-internal carotid artery in 100adult healthy male Wister rats. Rats in the treatment group were injected with 1.5％NRG-1β 5μL in the internal carotid artery(ICA). Expression of MMP-9 was determined by immunohistochemical and immumofluorescent staining and western-blotting assay. Results  Hypoxia and ischemia can cause expression of MMP-9. With the prolongation of the ischemic time, an increased expression of MMP-9 was obtained in the control group. Expression of MMP-9 was decreased in the NRG-1β treatment group compared with the control group at the same time point and the corresponding region（P＜0.01）.   Conclusion  MMP-9 might contribute to inflammatory reaction after ischemia-reperfusion cerebral insult by different methods. NRG-1β might regulate the activation of MMP-9, disturb the development of inflammatory reaction, improve the micro-environment of neuron survival, delay the course and degree of the neuron by various methods, and further play a neuro-protective role in ischemia cerebral insult.

Key words: Neuregulins; Hypoxia-ischemia, brain; Reperfusion injury;Gelatinase B; Fluorescent antibody technique; Immunoblotting; Rats, Wistar