title: Effects of neuregulin on expression of MMP-9 and NSE in brain of ischemia/reperfusion rat.
abstract: The aim is to investigate the effects of neuregulin-1beta (NRG-1beta) on expression of matrix metalloproteinase-9 (MMP-9) and neuron-specific enolase (NSE) in brain tissue in rats following cerebral ischemia/reperfusion. One hundred and fifty adult healthy male Wistar rats were used in the present study. Ten of them were randomized into a sham-operation group (n = 10) and the rest suffered surgery operation of middle cerebral artery occlusion/reperfusion with intraluminal monofilament suture from the left external-internal carotid artery. As a result, 100 rats of successful models were randomly divided into a control group (n = 50) and a treatment group (n = 50). Rats in the treatment group were injected 1.5% NRG-1beta at a dosage of 0.3 microg/kg from the stump of the left external carotid artery into the internal carotid artery. The expressions of MMP-9 and NSE proteins were determined by immunohistochemical, immunofluorescent double labeling, and Western blot assay. Ischemia/reperfusion induced morphological changes of brain tissue, including neurocyte shrinkage, chromatin condensation, nuclei fragment, and gliacyte and endothelial cell swelling. NRG-1beta obviously reduced and delayed the cerebral damage. With the duration of ischemia, the expression of MMP-9 gradually increased in the control group. NRG-1beta decreased the level of MMP-9 compared with that in the control group (P < 0.01). NSE immunoreaction transiently elevated at the early stage of cerebral ischemia insult, and then gradually decreased in the control group. The administration of NRG-1beta significantly increased the level of NSE, and thus delayed the time and the degree of neuron damage. There were statistical differences in contrast to the control group (P < 0.01). There was no relationship between the expressions of the two proteins. MMP-9 might aim at various target cells at different stages and contribute to the inflammatory reaction after cerebral ischemia-reperfusion insult. NRG-1beta inhibits the activation of MMP-9 and development of inflammation, enhances the activity of NSE, improves the microenvironment of neuron survivals, and delays the phase of irreversible neuron necrosis. Therefore, NRG-1beta may play a neuroprotective role in cerebral ischemia/reperfusion.
authors.affiliation: Institute of Cerebrovascular Diseases of Affiliated Hospital, Qingdao University Medical College, Qingdao, 266003, China. liqin1015@yahoo.com.cn
authors.forename: Qin
authors.initials: Q
authors.lastname: Li
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Yin-lin
authors.initials: YL
authors.lastname: Ge
authors.forename: Yuan-wu
authors.initials: YW
authors.lastname: Mei
authors.forename: Yun-liang
authors.initials: YL
authors.lastname: Guo
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D006801:Humans; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D020890:Neuregulin-1 / Q000235:genetics / Q000378:metabolism*; D010751:Phosphopyruvate Hydratase / Q000235:genetics / Q000378:metabolism*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology
chemical_list: D020890:Neuregulin-1; C117467:neuregulin beta; D020780:Matrix Metalloproteinase 9; D010751:Phosphopyruvate Hydratase