Kazan S, Karasoy M, Baloğlu H, Tuncer R
Department of Neurosurgery, Akdeniz University, Faculty of Medicine, Antalya, Turkey.
Acta Neurochir (Wien). 1999;141(9):979-87. doi: 10.1007/s007010050405.
We investigated the effect of mild hypothermia (32-34 degrees C), mannitol and insulin - induced hypoglycaemia on the ischaemic infarct volume on permanent middle cerebral artery occlusion with bilateral carotid artery ligation in rats. Temporalis muscle temperature as an indicator of brain temperature was monitored throughout the experiment in all rats, which were randomly divided into seven groups. During ischaemia, control rats received intravenous saline in a normothermic condition; treated rats had hypothermia and intravenous saline, hypothermia and mannitol, normothermia and mannitol, normothermia and insulin, normothermia, insulin and glucose, and hypothermia and insulin applied. After the experiment, the animals were killed, and brain sections were stained with haematoxylin and eosin. Images of infarct areas were determined using a camera attached to the microscope, and analysed by image analysis software. The total volume of infarcted tissue, right hemispheric volume, and the percentage of infarction were determined at the end of the image analysis investigation. The infarct volume on the control group was found to be 128.16+/-6.67 mm(3). Infarct volumes in hypothermic groups were significantly smaller than those of the control group (p<0.05). There were no significant differences between infarct volumes in the hypothermic groups. However, we found that hypothermia plus mannitol have the greatest neuro-protective effect. In normothermic rats, the infarct volume decreased proportionally but not statistically (p>0.05) whether mannitol or insulin was given. Our results also demonstrate that pre-, and post-ischaemic serum glucose concentrations influence the volume of infarction. Rats that had had pre-ischaemic high serum glucose concentrations had a higher volume of infarct than the hypothermic rats (p<0.05), while rats with post-ischaemic low serum glucose concentrations had a lower volume of infarct than the control rats.
