A review of in vivo 1H magnetic resonance spectroscopy of cerebral ischemia in rats.

A number of metabolic alterations are initiated by cerebral ischemia including dramatic increases in lactate concentration, decreases in N-acetylaspartate, choline, and creatine concentrations, as well as changes in amino acid levels. A review of proton nuclear magnetic resonance spectroscopy studies of focal and global cerebral ischemia in rats is presented here. In particular, studies in neonatal rats have shown that a continued elevation of lactate levels without recovery after hypoxia-ischemia or a decrease in N-acetylaspartate concentration at any time are indicative of deleterious outcome. Studies of the effect of temperature on ischemic damage in a model of focal ischemia showed that outcome improved with mild hypothermia. Again, lack of recovery of lactate upon reperfusion was shown to be indicative of poor outcome. Dichloroacetic acid was used to treat rats with focal ischemic damage. Animals subjected to transient ischemia that were treated with dichloroacetic acid showed significant decreases in lactate concentration.