Effects Of The Intervention Of NO Precursor/donor On The Cerebral Ischemia And OX42, MAP2 Positive Cell Responses In Rat

Background and Purpose:Endogenous Nitric oxide (NO) was discovered in 1980s , from then on , NO play very important physiology and pathology roles. As an important messenger molecule, NO participate various physiology and pathology processes and has extensive biological action. NO has a Janus nature, it can either function as a beneficial or venomous agent in nervous system. Whether NO is helpful or harmful depends on a variety of factors, such as the cellular environment, site of action and the time in which NO is released, the quantity and concentration of NO, the state of oxidation-reduction and so on. In order to validate whether NO precursor / donor had the protection effects on brain injury in acute ischemic stage and further to approach a better way to prevention and cure cerebral ischemia, we employed the model of transient middle cerebral artery occlusion (MCAO), which was intervened with Arginine and Nitroglycerin .Material and Methods:66 healthy male adult Sprague-Dawley white rats were divided into four groups randomly: (1)Sham-operated group(n=12); (2) MCAO group (n=18); (3) Nitroglycerin Group (n=18):Nitroglycerin was intervened immediately after reperfusion; (4) Arginine group(n=18): Arginine was intervened immediately after reperfusion; Every group was divided into two subgroups according to the different sacrificed time point :ischemia 2h and reperfusion 3h; ischemia 2h and reperfusion 24h;3h time point was 6 rats, 24h time point: Sham-operated group was 6 rats, other groups were 12 rats.Longa score was recorded at different time points. Animals were sacrificed after record. Infarct volume was assessed by TTC (2, 3, 5-triphenyl Tetrazolium chloride). The brain sections were Hematoxylin-eosin (HE) stained to show the histological change, neuron injury was detected by immunohistochemical stained with purified anti-rat CD11b/c (OX42) and immunofluorescence stained with microtubule associated protein-2 (MAP-2).Results:1. Longa score: The Arginine group and NG group had significant difference compared with MCAO group at 3h after reperfusion (P<0.025).There were no difference beteen various groups at 24h after reperfusion.2. TTC: The Arginine, Nitroglycerin group had significant neuropro- tective effect compared with the MCAO group at 24h after reperfusion (P<0.05).3. (1) HE staining: There was no obvious neuron loss among each group at 3h after reperfusion. Bulks of neurons were lost in MCAO group at 24h after reperfusion. There were slightly decreased in Arginine, Nitroglycerin group compared with MCAO group.(2) OX42 Immunohistochemistry staining: Compared with MCAO group, the number of OX42 positive cells in the cortex of CP and CA1, CA3 of the hippocampus formation of Arginine ,Nitroglycerin group were significant decreased at 3h and 24h time point after reperfusion(P<0.05).(3) MAP-2 immunofluorescence staining: Compared with MCAO group, The optical density of MAP2 positive cells In the cortex of CP and CA1, CA3 of the hippocampus formation of Arginine ,Nitroglycerin group was significant decreased at 3h and 24h time point after reperfusion(P<0.05).Conclusion:1. NO precursor/ donor has significant neuroprotection after focal cerebral ischemia by photothrombosis in rat.2. With the way of reducing the number and activity of OX42 positive cells, inhibiting the degradation of MAP2 positive cells and recover bulk cytoskeleton structure .The intervention of NO precursor/ donor in the MCAO model, has the protection effects on brain injury in acute ischemic stage.