| Objective Detect emulsified isoflurane (Emulsified isoflurane, EI) intravenous anesthesia's influence on learning and memory and plasma corticosterone levels of adult male SD rats. Observed the behavior of rats through the step down test and Morris water maze test; Detect plasma corticosterone levels by Enzyme-linked Immunosorbent Assay (Enzyme-linked Immunosorbent Assay, ELISA), to investigate whether emulsified isoflurane affected learning and memory and plasma corticosterone levels, to clarify whether emulsified isoflurane and postoperative cognitive dysfunction (Postoperative cognitive dysfunction, POCD) related.Methods Adult male SD rats (N= 36), be randomly divided into 6 groups, control group (n= 6), NS group (n= 6), EI group (n= 6), EI+Morris water maze group (n= 6), step down test group (n= 6), EI+step down test group (n= 6). (1)Control group was completely blank in control group, no treatment. (2) NS groups needed not step down test and Morris water maze test; intravenous injection of NS lml/kg on 11:00-12:00. (3) EI Group needed not step down test and Morris water maze test; intravenous injection of 8% EI (volume ratio) lml/kg on 11:00-12:00. (4) EI+Morris water maze test group had Morris water maze place navigation training, training 08:00-12:00 in daily,4 times/day for 5 days, with behavioral observation, recording navigation test escape latency time. No.5 day after Morris water maze place navigation training,10:00-11:00, Morris water maze search capability test, record spatial search capability within the target quadrant of rat in 2 min. Experiment to keep the environment quiet and water maze around the light source and location of fixed objects. No.5 day after Morris water maze place navigation training,on 11:00-12:00, intravenous injection of 8% emulsified isoflurane lml/kg that 120mg/kg,6 hours after anesthesia on 18:00-19:00, completed a Morris water maze test. (5) step down test group:on 18:00-19:00 to step down test; before the 24h experimental training. (6) EI+step down test group,on 11:00-12:00 e, intravenous injection 8% emulsified isoflurane 1 ml/kg or 120mg/kg, after anesthesia 6 hours,has step down test on 18:00-19:00; before the 24h experimental training. EI+Morris water maze group, EI+ step down test group and the step down test group experiment on the same day, NS group injected with NS on the same day, EI group injected with EI on the same day, the control group and the EI group on the same day,19:00-20:00, the rats are anesthesiaed by intraperitoneal injection of 10% chloral hydrate (0.4ml/100g), taked 2-3ml of blood from the eyes. blood is placed in the heparin tube on ice, centrifugaled under 4000r/min for 15min on 0-4℃, the plasma is taked. Detected the rat's plasma corticosterone levels by Enzyme-linked immunosorbent assay.Results 1. Morris water maze test:①EI+Morris water maze before the intravenous injection of navigation test escape latency (seconds, x), the first 1-5 days were 42.04, 22.79,11.08,13.29,10.96. EI+Morris water maze after injection navigation test escape latency (seconds, x) for 12.66. EI+Morris water maze after injection navigation test escape latency and EI+Morris water maze before intravenous navigation test escape latency on day 5 compared with no significant difference (P＞0.05).②EI intravenous injection before the Morris water maze test 2min search capability within target quadrant time of rats (seconds, x) 46.15; EI intravenous injection before the Morris water maze test 2min search capability within target quadrant time of rats (seconds, x) 43.63. After El intravenous injection 6h of Morris water maze test 2min search capability inherent target quadrant time of rats and EI compared with that before injection showed no significant difference (P＞0.05).2. Step down results:EI+step down group, the latency of step down test (seconds, x) 221.83,184.66; the number of errors (x) were 0.67,0.5. EI+step down test group, the latency of jump and simple platform compared to the control group showed no significant difference (P＞0.05), EI+step down test group rats subjected to the number of errors to the control group showed no statistical significance (P＞0.05). After intravenous anesthesia in rats prompted EI 6h no change in learning and memory.3. Plasma corticosterone levels by Enzyme-linked immunosorbent assay:control group, NS, EI, EI+step down test group, EI+water maze, jumping rats plasma corticosterone levels (ng, x) were respectively 102.00,169.21,117.51,205.35,179.55, 200.22. Control group, NS, EI, EI+step down test group, EI+water maze group, corticosterone levels were jumping between group comparison, EI+step down test group compared with the control group difference was significantly (P= 0.038, P＜0.05), step down test group and control group difference was significant (P= 0.048, P＜0.05); NS, EI, EI+water maze group compared with the control group showed no significant difference (P＞0.05); NS, EI, EI+platform group, EI+water maze, platform group between the two groups showed no significant difference (P＞0.05). NS, EI, EI+group, EI+water maze, step down test group compared with no significant difference, but the NS, EI+step down test group, EI+water maze, and step down test group jumping plasma corticosterone levels mean significantly higher than the EI group. Tips EI 6h after a single intravenous plasma corticosterone levels were not significantly changed; step down test in rats significantly increased plasma corticosterone levels; guess the water maze test, step down test, NS intravenous injection may affected the potential of plasma corticosterone levels factors.Conclusion Learning and memory and plasma corticosterone levels of rats had no chang significantly after a single emulsified isoflurane intravenous anesthesia 6h. Objective Deteced Emulsified isoflurane anesthesia on adult male SD rats affect spatial learning, memory. Conducted by Morris water maze test behavior observed and recorded escape latency of Morris water maze navigation test, time in the quadrant where the platform of Morris water maze spatial search capability test; to investigate whether emulsified isoflurane has influence in spatial learning and memory, to clarify whether emulsified isoflurane and postoperative cognitive dysfunction (Postoperative cognitive dysfunction, POCD) have related.Methods Adult male SD rats (n= 30), were divided randomly into NS group (n= 6), C group (n= 24, points C1, C2, C3, C4 four sub-group, n= 6). NS group is control group; C group is test group. The rats have Morris water maze place navigation training, training in daily 08:00-12:00,4 times/day for 5 days, for behavior to observe and record the escape latency navigation test of time. Day 5 Morris water maze place navigation training after,10:00-11:00 line search capability Morris water maze test, record test spatial search capability within the target quadrant stay in 2min of rats. Experiment to keep the environment quiet and water maze around the light source and location of fixed objects. Day 5 Morris water maze place navigation training after the end of,11:00-12:00, NS Group to intravenous injection of NS lml/kg, C group were injected with 8% emulsified isoflurane lml/kg or 120mg/kg. NS group 6 hours after intravenous injection of NS, C1 group of intravenous emulsified isoflurane anesthesia 6 hours after awakening, C2 Group anesthesia after 30 h (24 h+6 h), C3 group anesthesia after 54 h (48h+6 h)), C4 group anesthesia after 78 h (72h+6 h), at 18:00-19:00, the Morris water maze completion time and space navigation test search capability test.Results Morris water maze test:1. Morris water maze escape latency navigation test: Intravenous emulsified isoflurane anesthesia 1 day to 5 days Morris water maze place navigation training in escape latency (seconds, x) were NS Group 45.20,21.42,18.88, 17.96,14.63; C1 group 42.04,22.79,11.08,13.29,10.96; C2 group 48.29,14.00,13.50, 18.71,11.38; C3 group 46.54,19.54,10.50,11.38,8.50; C4 group 51.83,26.33,20.46, 12.58,11.50.Intravenous emulsified isoflurane anesthesia Morris water maze place navigation escape latency (seconds, x) NS, C1, C2, C3, C4 group were 21.42,12.66, 11.23,17.62,16.07. Intravenous emulsified isoflurane anesthesia before, Morris water maze navigation test on 1 day to day 5 NS, C1, C2, C3, C4 group escape latency between the two groups showed no significant difference (P＞0.05); NS, C1, C2, C3, C4 group escape latency of the first 2,3,4,5-days and 1 day group were statistically significant differences (P＜0.05); NS, C1, C2, C3, C4 group escape latency of rats with 2,3,4,5-day comparison group showed no significant difference (P＞0.05). Intravenous emulsified isoflurane anesthesia, C1, C2, C3, C4 group were intravenous emulsified isoflurane anesthesia after 6h,30 (24+6) h,54 (48+6) h,78 (72+6) h with the NS group rats 6h after intravenous injection of NS Morris water maze place navigation escape latency between the two groups showed no significant difference (P＞0.05). NS Group 5 days before intravenous injection NS NS after 6h Morris water maze place navigation in rats escape latency group difference was not statistically significant (P＞0.05); C1, C2, C3, C4 group 5 days intravenous emulsified isoflurane anesthesia before intravenous emulsified isoflurane anesthesia Morris water maze place navigation in rats group escape latency had no significant difference (P＞0.05).2. Morris water maze spatial search capability test:Morris water maze spatial search capability test NS, C1, C2, C3, C4 group of intravenous emulsified isoflurane in rats in the target quadrant before the time (seconds, x) were 38.73,43.63,48.98,47.29,45.61; emulsified isoflurane in rats after intravenous anesthesia in the target quadrant time (seconds, x) were 41.44,46.15,50.68,44.30,38.93.Intravenous emulsified isoflurane anesthesia before the NS, C1, C2, C3, C4 group of Morris water maze test in rats spatial search capability residence time in the target quadrant between the two groups showed no significant difference (P＞0.05); C1, C2, C3, C4 group were intravenous emulsified isoflurane anesthesia after 6h,30 (24+6) h,54 (48+6) h,78 (72+6) h, NS group after intravenous injection of NS 6h Morris water maze experiment space search ability test rats stay in the target quadrant between the two groups showed no significant difference (P＞0.05); NS group on day 5 intravenous NS before and after intravenous 6h Morris water maze test in rats searching residence time in the target quadrant group had no significant difference (P＞0.05); C1, C2, C3, C4 group of intravenous emulsified isoflurane anesthesia before intravenous emulsified isoflurane anesthesia Morris water maze test spatial search capability rats in the target quadrant time the group had no significant difference (P＞0.05).Conclusion Learning, memory and plasma corticosterone levels of rats had no chang significantly after a single emulsified isoflurane intravenous anesthesia 6-78h. The results of this study provide experimental support for clinical research and promote the use of emulsified isoflurane in the further.
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