Effectiveness of Brain Protection With Histidine-Tryptophan-Ketoglutarate Solutions

Tissue-protective solutions increase resistance of cells to ischemic conditions. Especially in carotid and aortic arch surgeries where the brain perfusion is at risk, these solutions may be beneficial to prevent ischemic brain damage. This study was designed to demonstrate the effectiveness of histidine-tryptophan-ketoglutarate (HTK) solution in increasing resistance of brain tissue to ischemic conditions.

Three separate randomized groups were created, each consisting of eight rabbits. The groups were called the ischemia, HTK and sham groups, respectively. In the ischemia group, temporary brain ischemia was created for 15 minutes by placing clamps on the bilateral subclavian and common carotid arteries. Then the clamps were removed, and the brain was reperfused for 30 minutes. In the HTK group, HTK solution was sent to the brain through the internal carotid artery before the same ischemia-reperfusion protocol was applied. Histopathological analyses using a visual scoring system to assess the degree of ischemic changes and the apoptotic cell index by TUNEL test were performed in all brain tissue samples.

Apoptotic cell indices of the HTK (20.6%) and sham (17.8%) groups were lower than the ischemia group (56.8%) (P < .05). Statistically significant differences were detected between all groups in categorical scores (P < .05).

It was shown that less ischemic damage occurs in the brain tissue with the use of HTK solution, and it may be a candidate approach to prevent the brain from ischemic insults during cerebrovascular surgery. Further studies are required to demonstrate its exact effectiveness, in terms of dose, duration, and temperature.