Effects of sevoflurane on neuronal cell damage after severe cerebral ischemia in rats

BACKGROUND The aim of this study was to investigate the neuroprotective effects of sevoflurane after severe forebrain ischemic injury. We also examined the relationship between the duration of ischemia and neuronal cell death. METHODS Male Sprague-Dawley rats (300-380 g) were subjected to 6 (each n = 6) or 10 min (each n = 10) of near-complete forebrain ischemia while anesthetized with either 50 mg/kg of zoletil given intraperitoneally or inhaled sevoflurane (2.3%). Ischemia was induced by bilateral common carotid artery occlusion plus hemorrhagic hypotension (26-30 mmHg). Histologic outcomes were measured 7 days after ischemia in CA1 pyramidal cells of the rat hippocampus. RESULTS The mean percentage of necrotic cells in the hippocampal CA1 area decreased in the sevoflurane group compared to the zoletil group (25% vs. 40% after 6 min ischemia, respectively: P = 0.004 and 44% vs. 54% after 10 min of ischemia, respectively P = 0.03). The percentage of apoptotic cells was similar in all groups. The percentage of necrotic cells in each anesthetic groups was significantly higher in the 10 min ischemia group compared to the 6 min ischemia group (P = 0.004 in the sevoflurane group, P = 0.03 in the zoletil group). CONCLUSIONS The present data show that sevoflurane has neuroprotective effects in rats subjected to near-complete cerebral ischemia. Longer duration of ischemia is associated with more neuronal injury when compared to ischemia of shorter duration.