Effects of Halothane and Isoflurane Anaesthesia on Antioxidant Enzymes in Dogs

Free radicals, along with the impairment of biological membranes and cellular structures and increased biological activity, come out with the results of the changes in the activity of the enzymes followed by the damages of cellular function and metabolism. This condition was attributed to the initiation effects of anaeshetics and other drugs which are used throughout the general anaesthesia. General anaesthesia which is constructed with using many drugs which have various physicochemical structures is a condition affecting lipid peroxidation in the organism directly or indirectly. In the frame of the study, the effects of halothane and isoflurane used in the anaesthesia on Malonyldialdehyde (MDA) concentration were investigated. The study was carried out on 14 dogs with various breeds, ages and sexes which were admitted to Kirikkale University, Faculty of Veterinary Medicine and with various signs of complaint and determined as healthy according to the clinical and haemotological examination. In the experiment, halothane (1-2.5%) and isoflurane (1-3%) were investigated as the anaesthetic substances. Diazepam (0.3 mg kg-1, IM) was administered as preanesthesia and thiopenthal sodium (10 mg kg-1, IV) was administered for the induction of anesthesia to dogs. Halothane and isoflurane were administered to the dogs in the first and second group, respectively. The duration of anaesthesia was determined as 60 min. Five blood samples were taken from the animals at the time prior to premedication, immediately before the gas anaesthesia, after 1 h of the initiation of anaesthesia, 3 and 24 h after the end of anaesthesia into the heparinated tubes. Malonyldialdehyde levels were measured in plasma. During the experimental period, body temperatures, heart rate, respiration rate and blood oxygen saturation values were recorded. Malondialdehyde levels measured during the halothane anaesthesia were numerically lower than those determined in isoflurane anaesthesia in same time period. However, they reached the same levels prior to the anaesthesia within 24 h in both groups. The differences between the two groups were statistically insignificant (p>0.05). Additionally, there were no significant differences in body temperature, heart rate, respiration rate and blood oxygen saturation values between the anaesthethic drugs. Results of the comparisons of time and drug type showed that anaesthesia procedures using both halothane and isoflurane did not have any negative effect on the oxidative metabolism in dogs.