Abstract: Object to observe the effects of treating acute ischemic stroke in rats by interventional administration of nitric oxide precurcer L-Arginine or nitric oxide donor Nitroglycerin . Method The right middle cerebral arteries of rats were occluded by insertion of a suture to duplicate ischemia-reperfusion models . Forty-two male SD rats were randomly divided into four groups: MCAO group(n=12) ;sham operation group(n=6) ; NG group (n=12) ; L-Arg group (n=12)，intracarotid arteries administrated respectively by NS、NS、NGand ARG.The four groups were subdivided into 2 groups according to reperfusion time (3h and 24h),measurement of Longa scores, NO2-/NO3- in serum, HE staining and immunohistochemical （SABC）method were utilized to assess the changes of ischemic brain tissues in different groups . Result OX -42 positive cells count of cortex and CA3 area of hippocampal: OX -42 positive cells were found ， their features could be seen at 3h after reperfusion . 24h the response of microglias was obvious , The volume and the number of the cells increased ( p<0.001) . NG group 3h and 24h, the microglias could be found unclearly , the number was little (P<0.05). L-Arg group 3h and 24h, the number was also little(P<0.05). Conclusion Interventional administration of NO precursor/donator has showed significant protective function to acute ischemia sroke in rats.

Key words: L-Arginine, Nitroglycerine, Ischemic stroke, OX-42