-Objective: to evaluate the neuroprotective effect of mild hypothermia during temporary focal ischemia in cats. Method: 20 cats underwent middle cerebral artery 60 minutes occlusion and 24 hours reperfusion: 10 under normothermia and 10 under mild hypothermia (32º c). Brain coronal sections 2mm thick were stained with 2,3,5-triphenyltetrazolium hydrochloride, photographed and evaluated with software for volume calculation. Results: cortical ischemia was found in 7 and basal ganglia ischemia in 8 animals of group 1 and in both regions in 5 animals of group 2 (no difference: p=0.6499 for cortical; p=0.3498 for basal ganglia). No ischemia was found in 5 animals of group 2 and in none of group 1 (significant difference, p=0.0325). the infarct volume was greater in group 1 than 2 (p=0.0433). Conclusion: Mild hypothermia did not interfere with location of ischemia, but it was effective for reducing the infarct volume.Key words: cats, focal cerebral ischemia, mild hypothermia, neuroprotection.Efeito neuroprotetor da hipotermia leve na isquemia cerebral focal temporária em gatos resuMo -Objetivo: Avaliar o efeito neuroprotetor da hipotermia leve na isquemia cerebral focal temporária em gatos. Método: oclusão da artéria cerebral média durante 60 minutos e 24 horas de reperfusão em 10 gatos sob normotermia e 10 sob hipotermia leve (32º c). secções cerebrais coronais de 2 mm coradas com 2,3,5-cloreto de trifeniltetrazolio, fotografadas e cálculos volumétricos (hemisférios/áreas isquêmi-cas) com programa específico. Resultados: Isquemia cortical em 7 e nos gânglios da base em 8 animais do grupo 1 e em ambas as regiões em 5 animais do grupo 2 (sem diferença: p=0,6499 cortical; p=0,3498 gân-glios da base). cinco animais do grupo 2 e nenhum do grupo 1 não apresentaram isquemia (diferença significante, p=0,0325). o volume do infarto foi maior no grupo 1 (p=0,0433). Conclusão: Hipotermia leve não interferiu com a localização da isquemia mas foi eficaz para reduzir o volume do infarto.PAlAvrAs-cHAve: gatos, isquemia cerebral focal, hipotermia leve, neuroproteção.
Dr. Benedicto Oscar Colli -Departamento de Cirurgia / HCFMRP -Campus Universitário USP -14048-900 Ribeirão Preto SP -Brasil. E-mail: bocolli@fmrp.usp.brBrain ischemia is common found in arterial vasospasm secondary to subarachnoid hemorrhage, by brain injury and during temporary occlusion of arteries during neurovascular procedures. despite attempts of using many strategies, the results of treatment for cerebral stroke are not ever satisfactory. the severity of brain lesion depends on the duration of ischemia, on the vessel occluded and on collateral circulation. several studies aiming better understanding of the ischemia/reperfusion pathophysiology and the improvement of brain protection in these phenomena have been done. In human being, these studies are generally clinical evaluations and image examinations that not allow detection of early cellular phenomena secondary to ischemia/reperfusion. experimental models have the advantage of better control of biolog...