Einfluss der Anästhetika Sevofluran und Propofol auf den nekrotischen und den apoptotischen Zelltod nach inkompletter zerebraler Hemisphärenischämie und Reperfusion in der Ratte über einen Beobachtungszeitraum von 28 Tagen

The long-term effect of sevoflurane and propofol on necrotic and apoptotic cell death after incomplete cerebral ischemia and reperfusion in the rat The present study investigates the effect of the anesthetic agents propofol and sevoflurane on irreversible cell damage (necrosis) and programmed cell death (apoptosis) for a time period of 28 days after incomplete transient cerebral ischemia and reperfusion in the rat. Ninety-six fasted male Sprague-Dawley rats (415±40g) were anesthetized, intubated and ventilated with 2 Vol% isoflurane and N2O/O2 (FiO2=0.33). Catheters were inserted into the right femoral artery and vein as well as in the right jugular vein for drug administration and blood withdrawal. At the end of surgery animals were randomly assigned to one of the following groups: control (n=32): 25 µg/kg/h fentanyl i.v. and N2O/O2 (FiO2=0.33); propofol (n=32): 25 µg/kg/h propofol i.v. and O2/air (FiO2=0.33); sevoflurane (n=32) 2 Vol% sevoflurane in O2/air (FiO2=0.33). Ischemia (45min) was produced by unilateral common carotid artery occlusion plus hemorrhagic hypotension (MAP=40 mmHg). Pericranial temperature (37.5°C), arterial blood gases and pH were maintained constant. Animals were then randomly assigned to a postischemic reperfusion time of 01, 03, 07, or 28 days. At the end of the observation period the animals were deeply anesthetized and killed, the brains were removed, frozen at –70 °C, and sectioned for further evaluation. Hematoxylin-Eosin staining was used to evaluate eosinophilic cell damage and tissue damage in 7 μm sections in the hippocampus, dentate gyrus and surrounding tissues. Immunohistochemistry was used to detect activated caspase-3 as a marker of apoptotic cell death. To distinguish activated caspase-3-positive neurons from other cells, a double staining, using the specific neuronal marker NeuN was used additionally. The results showed that with the exception of one animal in the sevoflurane group there is no tissue damage or eosinophilic cell damage in either the propofol or the sevoflurane treated animals up to 28 days after ischemia. The only eosinophilic tissue damage was present in the control group. About one percent of the hippocampal neurons of all three groups were activated caspase-3-positive, independently of the observation period. Though there was a tendency in both treatment groups to a lower number of activated caspase-3-positive cells. Results of the double staining showed that activated caspase-3, though mainly expressed in neurons, is also expressed in other cells. The present study showed that propofol and sevoflurane both produce a sustained inhibition of eosinophilic cell damage up to 28 days after incomplete cerebral ischemia in rats. Although the amount of activated caspase-3-positive neurons was similar in the three groups there was a tendency towards a lower number in the treatment groups compared to control. This suggests that neuroprotection seen with both, propofol and sevoflurane, involves anti-necrotic mechanisms rather than anti-apoptotic mechanisms. Further investigations will be required in the future to investigate the detailed mechanisms of propofol and sevoflurane to develop a successful treatment of ischemic insults and their consequences.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Ludwig-Maximilians-Universität

Year

2004

Author dc:creator

• Kellermann, Kristine

Repository record source_url

https://edoc.ub.uni-muenchen.de/1915/

OAI identifier oai:identifier

oai:edoc.ub.uni-muenchen.de:1915