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Objective To investigate the effects of isoflurane on receptor for advanced glycation endproducts (R(A)GE) expression in the hippocampus in rats. Methods Forty-five male 4-month-old and 45 male 24-month-old rats were used in this study. The animals were divided into 2 age groups ( n = 45 each): the aged group (group O) and the adult group (group A). Each group was further divided into 3 subgroups ( n = 15 each):Ⅰ control subgroup (group OC,AC) inhaled 30% O2 in air; 1 single isoflurane inhalation subgroup (group OS,AS) inhaled 1.5 % isoflurane for 2 h and Ⅲ repeated isoflurane inhalation subgroup (group OR, AR) inhaled 1.5 % isoflurane 2 h per day for 3 days. One day after isoflurane inhalation, learning and memory function was assessed using Morris water maze test in 8 animals in each subgroup. The rest of each subgroup were killed and their hippocampi were immediately isolataed for detection of RAGE mRNA and protein expression by RT-PCR and immuno-histochemistry. Results The cognitive function was impaired after signle or repeataed isoflurane anesthesia as compared with control animals in both aged and adult groups. The expression of RACE mRNA and protein in hippocampus was significantly increased after either single or repeated isoflurane anesthesia in aged group but only after repeated isoflurane anesthesia in adult gpoup. There was no significant difference in RAGE mRNA and protein expression in the hippocampus between control and single isoflurane inhalation animals in adult group. Conclusion Isoflurane can reduce learning and memory function in both aged and adult rats by increasing RAGE expression in hippocampus especially in aged rats.
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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 observe the change in memory of aged rats and the expression of alpha 4 acetylcholine receptor in hippocampus 5 h after inhalation of 1.2% isoflurane.Methods Fifty healthy adult and 50 aged SD rats were randomly divided into aged normal control group(A0),aged water labyrinth normal control group(WA0),1 day isoflurane aged water labyrinth group(WA1),3-day isoflurane aged water labyrinth group(WA3),7-day isoflurane aged water labyrinth group(WA7),adult normal control group(B0), adult water labyrinth normal control group(WB0),adult 1 day isoflurane water labyrinth group(WB1),3-day isoflurane water labyrinth group(WB3),and 7-day isoflurane water labyrinth group(WB7),10 rats in each group.Memory of rats in WA1,WA3,WA7 groups was detected 5 h after inhalation of 1.2% isoflurane while memory in rats of WB1,WB3 and WB7 groups was detected during the Morris water maze testing.The rats in A0,WA0,WA7,B0,WB0 and WB7 groups were killed on day 7 to detect the expression of ?4 acetylcholine receptor by Westernblotting for observation of changes in distribution of positive immune reaction cells in hippocampus.Results Water maze test showed that there was no significant difference in expression of alpha 4 acetylcholine receptor between WA0 and WB0 groups.However,the expression level of alpha 4 acetylcholine receptor was significantly lower in latent period of WA1 than in latent period of WA0,WB0 and WB7 groups(P