Hypothermia selectively protects the anterior forebrain mesocircuit during global cerebral ischemia

Hypothermia is an important protective strategy against global cerebral ischemia following cardiac arrest. However, the mechanisms of hypothermia underlying the changes in different regions and connections of the brain have not been fully elucidated. This study aims to identify the metabolic nodes and connection integrity of specific brain regions in rats with global cerebral ischemia that are most affected by hypothermia treatment. ¹⁸F-fluorodeoxyglucose positron emission tomography was used to quantitatively determine glucose metabolism in different brain regions in a rat model of global cerebral ischemia established at 31-33°C. Diffusion tensor imaging was also used to reconstruct and explore the brain connections involved. The results showed that, compared with the model rats established at 37-37.5°C, the rat models of global cerebral ischemia established at 31-33°C had smaller hypometabolic regions in the thalamus and primary sensory areas and sustained no obvious thalamic injury. Hypothermia selectively preserved the integrity of the anterior forebrain mesocircuit, exhibiting protective effects on the brain during the global cerebral ischemia. The study was approved by the Institutional Animal Care and Use Committee at Capital Medical University (approval No. XW-AD318-97-019) on December 15, 2019.