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Objective To investigate the effects of inhalation of different concentrations of isoflurane on the expression of cytochrome c ( Cyt c) in hippocampus in aged rats.Methods Sixty-three aged male SD rats (20 months) weighing 500-600 g were randomly divided into 3 groups(n=21each):control group inhaling 30%O2 for 2h (group C) and 2 isoflurane groups anesthetized with 0.75 % and 1.5 % isoflurane in 30 % O2 for 2 h respectively (group Ⅰ1 and Ⅰ2 ).Arterial blood samples were obtained from 5 rats at 30 min, 1 and 2 h of anesthesia for blood gas analysis. Eight animals were killed at 24 h after anesthesia in each group.Their hippocampi were immediately removed for determination of Gyt c expression by immuno-histochemistry and Western blot analysis.Cognitive function was assessed by Morris water maze test the day before experiment and once a day for 6 consecutive days starting from the 1st postoperative day.Results The Cyt c expression in hippocampus was significantly increased in Ⅰ1 and Ⅰ2 groups in a concentration-dependent manner as compared with group C.The escape latency was significantly prolonged and the frequency of crossing the original platform and the duration of staying at the original platform quadrant were decreased in group Ⅰ1 and Ⅰ2 compared with group C.Conclusion Inhalation of isoflurane anesthesia can decrease cognitive function through up-regulating the Gyt c expression in hippocampus in aged rats.
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Objective To explore the effect of isofluranee on receptor for advanced glycation end products (RAGE) expression of hippocampus and learning and memory function in rats. Methods 24-month Sprague-Dawley male rats (n=45) and 4-month Sprague-Dawley male rats (n=45) were randomly divided into six groups with 15 rats each group. Group C1 (aged control group),group C2(adult control group) breath 30% oxygen and air mixed gas; Group S1(single inhalation of isoflurane aged group),Group S2(single inhalation of isoflurane adult group)were anesthetized with 1.5% isoflurane,breath 30% oxygen and air mixed gas for 2h;Group R1(Repeated inhalation of isoflurane aged group), group R2(Repeated inhalation of isoflurane adult group) were anesthetized with 1.5% isoflurane,breath 30% oxygen and air mixed gas 2h a day for three days. Eight rats randomly selected from each group were killed and their hippocampus were immediately isolated for detection of RAGE expression by immunohistochemistry and RT-PCR after accomplished treatment 24h. The remained rats' learning and memory function were assessed using Morris water-maze test. Results The results of Morris water-maze test showed that the times of acerossing the original platform and the time consumption of staying the original platform quadrant was shorter in group S1 and group R1,but the escape latency was longer than group C1(escape latency C1 (9.42± 2.63)s,S1(13.20±3.85)s,R1(17.20±3.44)s, F=12.773, P<0.05). In the group R2,the escape latency was longer but the times of accrossing the original platform and the time consumption of staying the original plat-form quadrant was shorter than group C2 (times of accrossing the original platform C1(7.30±2.40), S1(3.90± 2.42),R1(3.44±2.40), F=7.448, P<0.01).To contrast with the group C2,there were no significant differ-enees in spatial probe test in the group S2(P>0.05). The levels of mRNA and protein of RAGE in hippocampus was significantly higher in group S1 and group R1 than group C1(RAGE mRNA expression C1(0.11±0.02),S1 (0.56±0.09), R1(0.73±0.14), F=179.447, P<0.01). To contrast with the group C2, there were no differ-ences found in the levels of mRNA and protein of RAGE in group S1(P>0.05), but it was higher in the group R2 (RAGE mRNA express C2(0.22±0.04), R2 (0.41±0.08), F=40. 209, P < 0. 01). Conclusion Isoflurane can reduce learning and memory function in both aged and adult rats, but aged rats are particularly significant im-pacted. This effect may be induced by the increase of RAGE expression in hippocampas.
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Objective To compare the postoperative cognition function after propofol intravenous versus isoflurane inhalation anesthesia in off-pump coronary artery bypass grafting (CABG) patients. Methods 30 ASA Ⅱ - Ⅲ patients undergoing off-pump CABG were randomly assigned to two groups. Following induction of anesthesia,isoflurane inhalation( group A ) or propofol intravenous (group B ) were adjusted to maintain comparable depth of anesthesia state. The mini-mental state examination (MMSE) was used to assess the cognitive function 1 day before and 4 days after the operation. Results There were 5 patients suffered postoperative cognitive dysfunction in group A, and 3 cases in group B . But compared with the preoperative( group A (29.13 ± 0. 83 ), group B (29.13 ±1. 13 ) ) ,the MMSE score at 4 days in group A ( 28.73 ± 1.03 ) were lower( t = 2.45, P ＜ 0.05 ), there was no difference in group B( 28.93 ± 1.16)at 4 days( t = 1.87, P ＞ 0. 05 ). Conclusion Both propofol intravenous anesthesia and isoflurane inhalation anesthesia in off-pump CABG may contribute to postoperative cognitive dysfunction, propofol intravenous anesthesia is advantageous over isoflurane inhalation anesthesia.
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The hemodynamic and metabolic changes during induced hypotension with isoflurane (isoflurane group) or sodium nitroprusside (SNP group) were observed in twelve mongrel dogs. These hypotensive effects were evaluated at 30 and 60 minutes after the mean arterial blood pressure was lowered to 50% from the control. Hemodynamic changes were evaluated by measuring systemic arterial blood pressure, heart rate, central venous pressure, pulmonary capillary wedge pressure, cardiac output, systemic vascular resistance and pulmonary vascular resistance. Metabolic changes were evaluated by measuring serum lactate and pyruvate, arterio-venous oxygen content difference and oxygen extraction rate. We also compared the ventilatory effect of hypotensive anesthesia by blood gas analysis. The results were as follows: 1. Isoflurane inhalation 2-4% or SNP infusion 10-20 micrograms/kg/min was required to reduce the mean arterial pressure to 50% of the control. 2. Heart rate was decreased slightly in the isoflurane group but significantly decreased in the SNP group. 3. There were no significant changes in central venous pressure and pulmonary capillary wedge pressure in either group. 4. Cardiac output was reduced in both groups but was more severe in the isoflurane group. 5. Systemic vascular resistance was decreased by 36% in the isoflurane group and 47% in the SNP group. 6. Acidosis was apparent and did not recover to the control until 30 minutes after recovery in the SNP group. 7. Arterio-venous oxygen difference was increased during hypotension in the isoflurane group probably due to decreased cardiac output. 8. The lactate/pyruvate ratio increased slightly in the SNP group.
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Cães , Anestesia , Animais , Hemodinâmica , Hipotensão Controlada , Isoflurano , Lactatos/metabolismo , Nitroprussiato , Piruvatos/metabolismo , Ácido PirúvicoRESUMO
Objective To investigate the effects of different target plasma concentrations of propofol given by TCI on end-tidal isoflurane concentration when the depth of anesthesia was maintained at BIS 50 and evaluate the reliability of electromyography (EMG) as an anesthesia depth monitor. Methods Sixty ASA Ⅰ-Ⅱ patients aged 40-65 yrs weighing 40-85 kg undergoing elective abdominal surgery under general anesthesia were randomly allocated to one of three groups with 20 patients in each group : group Ⅰ isoflurane; group Ⅱ isoflurane + TCI propofol (1 ?g?ml-1) and group Ⅲ isoflurane + TCI propofol (2 ?g?ml-1). The patients were premedicated with intramuscular phenobarbital 0.1 g and scopolamine 0.3 mg. Anesthesia was induced with midazolam 0.05 mg?kg , fentanyl 3 ?g?kg-1 and propofol 0.5-1.0 ?g?kg-1. Tracheal intubation was facilitated with vecuronium 0.12 mg?kg-1. After intubation anesthesia was maintained with isoflurane inhalation alone (group Ⅰ) or isoflurane combined with TCI propofol at a target plasma concentration of 1 ?g?ml-1 ( group Ⅱ) or 2 ?g?ml-1 ( group Ⅲ). MAP, HR, SpO2, PETCO2, BIS, EMG and end-tidal isoflurane concentration were continuously monitored during anesthesia. BIS was maintained at 45-55 after tracheal intubation during maintenance of anesthesia.Results The three groups were comparable with respect to age, sex, body weight, duration of anesthesia and the total amount of fentanyl used during anesthesia. There were no significant differences in MAP, HR and SpO2 among the 3 groups. When BIS was maintained at 50, the end-tidal isoflurane concentration was 0.76?0.03% (group Ⅰ), 0.43? 0.08% (group Ⅱ) and 0.21?0.07% (group Ⅲ) respectively. EMG was maintained at 26-29 during operation. During emergence from anesthesia EMG value increased with BIS value. When the patients opened their eyes at command EMG value was about 40. The correlation between BIS and EMG was poor. Conclusion At the samedepth of anesthesia (BIS = 50) the end-tidal isoflurane concentration was greatly reduced when combined with TCI propofol. EMG value decreases with increasing depth of anesthesia but as an anesthesia depth monitor it still needs improving.