| Objective: To investigate the effects of propofol and isoflurane on theplasma concentration of superoxide dismutase (SOD) and malondialdehyde(MDA) in the intracranial space-occupying lesion patients. Methods:FourtyASA physical status I and II patients with intracranial space-occupying lesionaged 19-70 years and weighing 45-77 kilograms were randomly divided intotwo groups, P and I. Anesthesia was induced with propofol 2-2.5mg·kg-1 (Pgroup, n=20) or 3% isoflurane (I group, n=20) adding fentanyl 2-4ug·kg-1 andvecuronium 0.1-0.15mg·kg-1. Anesthesia was maintained by continuous infusingpropofol 6-10mg·kg-1·h-1(P group) and inhaling 1%-2.5% of isoflurane (I group),besides intermittent boluses of fentanyl and vecuronium infusion. Venousplasma samples were taken simultaneously before induction (T1),one hour afterincision (T2), two hours after incision (T3), four hours after operation(T4),forty-eight hours after operation (T5) respectively to test the plasmaconcentration of SOD and MDA.Results: There is no statistically significant difference of the generalclinical condition, between the two groups(P>0.05) such as age, weight, sex,the time of operation and anesthesia. And there is no significant difference ofthe plasma concentration of SOD and MDA between the two groups at T1 andT2(P>0.05). The plasma concentration of SOD of group I is dramatically lowerthan that of group P at T3(P<0.01),T4 and T5(P<0.05). While the plasmaconcentration of MDA in group I is apparantly higher than that of group P at T3(P<0.01), T4 and T5(P<0.05).Discussion: There are series of pathophysiologic reactions in cerebralischemia and anoxemia. The principal point is that it generates much oxygenfree radical(OFR) which induces more lipid peroxidation. Moremalondialdehyde (MDA) generated, more superoxide dismutase (SOD) cost. Asa result, the plasma concentration of MDA increased sharply and the plasmaconcentration of SOD decreased sharply which damaged the membranes andbrain tissues. Testing the plasma concentration of SOD and MDA can reflectlipid peroxidation and content of oxygen free radical(OFR) in vivo.Intracranial space-occupying lesion can lead to cerebral ischemia andanoxemia. So cerebral protection and resuscitation is an important subject in theintracranial space-occupying lesion patients during neurosurgery.Propofol (2,6-diisopropylphenol) is a commonly used sedative andanesthetic .Its properties of protecting the brain against focal cerebral ischemiacould induce a reduction of cerebral metabolism, potentiation of γ-aminobutyric acid-mediated inhibition, and altered cerebral blood flow, whichmay beneficially redistribute flow. However, unlike most other anesthetics,propofol has shown direct antioxidant activity compared with the phenolichydroxyl group in its structure. The antioxidant property of propofol makes it asuperior anesthetic agent to combat ischemia.Isoflurane is a neotype sucking narcotic of halogen families. It has similarprotection effect on brain as propofol which is also antioxidant.This study indicated that the plasma concentration of MDA increased afterincision, on the contrary, SOD decreased. There is no significant difference ofthe plasma concentration of SOD and MDA between the two groups at T1 andT2(P>0.05). The plasma concentration of SOD in group I is significantly lowerthan that of group P at T3(P<0.01), T4 and T5(P<0.05). While the plasmaconcentration of MDA in group I is significantly higher than that of group P atT3(P<0.01), T4 and T5(P<0.05), which indicates that the propofol of clinicalanesthetic dosage can depress the generation of MDA, and increase the plasmaconcentration of SOD compared with the isoflurane. So propofol of clinicalanesthetic dosage can protect brain in the patients undergoing intracranialspace-occupying lesion operations through the antioxidant property.Conclusions: The propofol of clinical anesthetic dosage can obtain stableplasma concentration of SOD and MDA on the intracranial space-occupyinglesion patients perioperative, depress oxygen free radical which generates fromcerebral ischemia. and protect brain from intracranial spaceoccupying lesionoperation injury through the antioxidant property.
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