Metabolic alterations in the rat cerebellum following acute middle cerebral artery occlusion, as determined by 1H NMR spectroscopy

Supratentorial focal ischemia may reduce cerebral blood volume and cerebellar glucose metabolic rate contralateral to the region of ischemia. The present study investigated the effects of middle cerebral artery occlusion (MCAO) on cerebral metabolism in the ischemic cerebral hemisphere and the non-ischemic cerebellum in rats 1, 3, 9 and 24 h following ischemia using ex vivo proton nuclear magnetic resonance (H-1 NMR) spectroscopy. The results demonstrated that focal ischemia induced increases in the levels of lactate and alanine, and a decrease in succinate, as early as 1 h following ischemia in the left cerebral hemisphere and the right cerebellum. A continuous increase in lactate levels and decrease in creatine levels were detected in both cerebral areas 3 and 24 h post-MCAO. The most obvious difference between the two cerebral areas was that there was no statistically significant difference in N-acetyl aspartate (NAA) levels in the right cerebellum at all time points; however, the amino acid levels of NAA in the left cerebral hemisphere were markedly decreased 3, 9 and 24 h post-MCAO. In addition, an obvious increase in glutamine was observed in the right and left cerebellum at 3, 9 and 24 h post-MCAO. Furthermore, the present study demonstrated that -aminobutyric acid levels were decreased at 1 h in the left and right cerebellum and were evidently increased at 24 h in the right cerebellum post-MCAO. In conclusion, supratentorial ischemia has been indicated to affect the activities of the non-ischemic contralateral cerebellum. Therefore, these results suggested that an NMR-based metabonomic approach may be used as a potential means to elucidate cerebral and cerebellar metabolism following MCAO, which may help improve understanding regarding cerebral infarction at a molecular level. Ex vivo(1)H NMR analysis may be useful for the assessment of clinical biopsies.