RESUMO
Cerebral ischemia not only causes pathological changes in the ischemic areas but also induces a series of secondary changes in more distal brain regions (such as the contralateral cerebral hemisphere). The impact of supratentorial lesions, which are the most common type of lesion, on the contralateral cerebellum has been studied in patients by positron emission tomography, single photon emission computed tomography, magnetic resonance imaging and diffusion tensor imaging. In the present study, we investigated metabolite changes in the contralateral cerebral hemisphere after supratentorial unilateral ischemia using nuclear magnetic resonance spectroscopy-based metabonomics. The permanent middle cerebral artery occlusion model of ischemic stroke was established in rats. Rats were randomly divided into the middle cerebral artery occlusion 1-, 3-, 9- and 24-hour groups and the sham group. 1H nuclear magnetic resonance spectroscopy was used to detect metabolites in the left and right cerebral hemispheres. Compared with the sham group, the concentrations of lactate, alanine, γ-aminobutyric acid, choline and glycine in the ischemic cerebral hemisphere were increased in the acute stage, while the concentrations of N-acetyl aspartate, creatinine, glutamate and aspartate were decreased. This demonstrates that there is an upregulation of anaerobic glycolysis (shown by the increase in lactate), a perturbation of choline metabolism (suggested by the increase in choline), neuronal cell damage (shown by the decrease in N-acetyl aspartate) and neurotransmitter imbalance (evidenced by the increase in γ-aminobutyric acid and glycine and by the decrease in glutamate and aspartate) in the acute stage of cerebral ischemia. In the contralateral hemisphere, the concentrations of lactate, alanine, glycine, choline and aspartate were increased, while the concentrations of γ-aminobutyric acid, glutamate and creatinine were decreased. This suggests that there is a difference in the metabolite changes induced by ischemic injury in the contralateral and ipsilateral cerebral hemispheres. Our findings demonstrate the presence of characteristic changes in metabolites in the contralateral hemisphere and suggest that they are most likely caused by metabolic changes in the ischemic hemisphere.
RESUMO
According to the theory of traditional Chinese medicine, cerebral infarction results from blood stasis, and the method of quickening the blood and dispelling stasis is used to treat cerebral infarct. salvia miltorrhiza bunge (SM) is a Chinese herb, which is considered to have an action of quickening the blood and dispelling stasis, and is frequently used to treat related disorders of blood stasis such as cerebrovascular accident and ischemic heart disease. The aim of the present study was to investigate the effect of SM on cerebral infarct in ischemia-reperfusion injured rats. A total of 30 Sprague-Dawley (SD) rats were studied. A model of focal cerebral infarct was developed by occluding both common carotid arteries and the right middle cerebral artery for 90 minutes. After 24 hours reperfusion, the rats were killed and the brain tissue was stained with 2, 3, 5-triphenyl-tetrazolium chloride (TTC). The areas of cerebral infarct were calculated, and lumino-chemiluminesence (CL) counts and lucigenin-CL counts of peripheral blood taken at this time were measured. The changes in the area of cerebral infarct were used as an index to evaluate the effect of SM on cerebral infarct. The results indicated that pretreatment with intraperitoneal injection of 30 mg/kg and 15 mg/kg SM reduced the area of cerebral infarct and also reduced the luminol-CL counts of peripheral blood in ischemia-reperfusion injured rats. This study has demonstrated that SM can reduce the area of cerebral infarct in ischemia-reperfusion injured rats, suggesting it may be useful in the treatment of cerebral infarct in humans. The therapeutic effect of SM may be partly due to its free radical scavenging activities.