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Objective To investigate the effects of skin/muscle incision and retraction(SMIR)on mechanical paw withdrawal threshold and the ability of spatial learning and memory in immature rats after adulthood. Methods 27 male SD rats aged 3 weeks and weighing 60 ~ 80 g were randomly divided into 3 groups(n = 9):control group(group C),sham operation group(group Sham)and skin/muscle incision and retraction group (group SMIR). Group SMIR received operation for skin/muscle incision and retraction. Sham group received skin/muscle incision but no retraction.No surgery was operated on C group. Pain behavior was assessed by mechanical paw withdrawal threshold(MWT)to von Frey filament stimulation before and 1,3,7,12,22 and 32 days after operation.The effects of spatial learning and memory function were assessed by Morris water-maze test at 33 days after operation. Results Mechanical paw withdrawal threshold of group SMIR decreased 1 day after operation (P<0.05)and showed no significant difference before and 3,7,12,22,32 days after operation in 3 groups(P >0.05). In Morris water-maze test,compared with Sham and C group,the average escape latency in SMIR was sig-nificantly longer in the water maze navigation experiment(P < 0.01);the ratios of time and path in the quadrant of the platform were obviously lower in SMIR(P < 0.01). There was no statistical difference between sham and C group(P>0.05).Conclusion SMIR did not cause chronic pain but may cause a decrease in the ability of spatial learning and memory in immature rats.
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Objective To observe a new phosphodiesterase-4 inhibitor Ro 20-1724 on ketamine anesthesia-induced learning and memory impairment and cAMP/PKA-CREB-BDNF signal pathway in immature rats.Methods Twenty-four 21 day-old SD rats were randomly divided into 4 groups (n=6 each):control group (group C) ;ketamine group (group K) ;ketamine+Ro 20-1724 group(group K+Ro) and ketamine+vehicle (0.1％ ethanol) group (group K+E).Ketamine 70 mg/kg was injected intraperitoneally(IP) once a day for 7 consecutive days in groups K,K+Ro,and K+E.Ro 20-1724 0.5 mg/kg and equal volume of vehicle were injected IP at 30 min after IP ketamine each time respectively.Morris water maze was used to assess learning and memory ability after 2 days normal feeding,the escape latency and frequency of passing the platform were recorded.The animals were killed after water maze test and the cAMP,PKA,p-CREB,and BDNF protein expression in hippocampus were detected.Results Repetitive ketamine anesthesia significantly prolonged the escape latency (P＜0.01),decreased the frequency of passing the platform(P＜0.01),and down-regulated the expression of cAMP,PKA,p-CREB,and BDNF protein ((280±31) pmol/mg vs (210± 19) mol/mg,P＜0.01 ; 1.32±0.11 vs 1.13±0.12,P＜0.01 ; 2.61 ±0.22 vs 2.03 ± ±0.19,P＜0.01 ; 1.51 ±0.14 vs 1.16±0.10,P＜0.05) ; Compared with group K,Ro 20-172,significantly attenuated the escape latency time(P＜0.05,P＜0.01)and increased the frequency of passing the platform(P＜0.01),and ameliorated the expression of cAMP,PKA,p-CREB,and BDNF protein ((210± 19) pmoL/mg vs (240± 27) pmol/mg,P ＜0.05;1.13±0.12 vs 1.28±0.12,P＜0.05;2.03±0.19 vs 2.32±0.21,2.32±0.21;1.16±0.10 vs 1.37±0.11,P＜0.01).There was no difference between group K+Ro and group C,and between group K+E and group K(P＞0.05).Conclusion ketamine anesthesia-induced learning and memory impairment can be improved by Ro 20-1724,and cAMP/PKA-CREB-BDNF signal pathway in hippocampus participated in the changes.
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Objective To evaluate the effect of Chinese herbal medicine immunomodulator on T lymphocyte immune function in peripheral blood and intestinal mucosa of immature rats with obstructive jaundice. Methods Three-weeks Wistar rats were randomly divided into four groups. (n= 12, in each): normal control group, sham operation group, obstructive jaundice (OJ) group, OJ + Chinese herbal medicine immunomodulator (OJ+ZY) group. Except for the normal control group, the others' bile duct stones were ligatured to establish rat models with obstructive jaundice. The percentage of CD4+ and CD8+ tlymphocytes and the ratio of CD4+/CD8+ in peripheral blood and intestinal mucosa of immature rats was detected by flow cytometry. Results The percentage of CD4+ cell [(36.2 ±4.2)%, (28.8±1.8)% respectively] and the ratio of CD4+/CD8+ [(1.14±0.39), (1.37±0.34)respectively] in OJ group were lower than those in normal control group [peripheral blood: CD4+(41.5±5.3)%,CD4+/CD8+(1.37±0.19); intestinal mucosa: CD4+(32.3± 2.4)%, CD4+/CD8+ (1.84+0.28) and sham operation group (peripheral blood: CD4+ (41.2±5.5)%, CD4+/CD8+ (1.45±0.27); intestinal mucosa: CD4+(31.5 ± 2.7)%, CD4+/CD8+ (1.63±0.58)] . The difference was statistical significant(P<0.05). The percentage of CD4+ cell [(42.7±6.3)%, (33.6±2.4)% respectively] and the ratio of CD4+/CD8+ [(1.56±0.46), (1.84±0.56)respectively] in OJ+ZY group, were higher than those in OJ group(P<0.05). The difference was statistical significant(P<0.05). Conclusion Chinese herbal medicine immunomodulator can increase T lymphocyte immune function in immature rats with obstructive jaundice, but has no significance in normal control group as well as sham operation group.
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Objective To evaluate the effect of Astragalus on T lymphocyte immune function in peripheral blood and intestinal mucosa of immature rats with obstructive jaundice. Methods Three-week-old Wistar rats were randomly divided into four groups(n=12,in each):control group, sham operation group, obstructive jaundice(OJ)group,OJ+Astragalus (OJ+A)group.The percentage of CD4 and CD8 T lymphocytes, the ratio of CD4 to CD8 in peripheral blood and intestinal mucosa of immature rats was detected by flow cytometry. Result The percentage of CD4+ cell and the ratio of CD4 to CD8 in the OJ group were lower than those in the control group and the sham operation group,with significant difference(P＜0.05).The percentage of CD4 cell and the ratio of CD4 to CD8 in the OJ+A group were higher than those in the OJ group(P＜0.05).Conclusion Astragalus can increase T lymphocyte immune function in OJ immature rats.
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PURPOSE: Vigabatrin is a widely used antiepileptic drug that greatly increases whole brain gamma- aminobutyric acid(GABA). But little is known about the anticonvulsant effect of vigabatrin on pilocarpine-induced seizures in the immature rats. This study was conducted to determine the effects of vigabatrin on pilocarpine-induced seizures in the immature rats. METHODS: Six to eight day old Sprague-Dawley rats were classified into control(n=5) and vigabatrin-treated(n=5) groups that were pretreated with 30mg/kg of vigabatrin. Animals received vigabatrin or saline, intraperitonealy, for 6 days, once a day. And on the 5th day, right and left cortical electrodes were placed in 10-14 day old animals using stereotaxic instrument. The following day 2.5-hour EEG recordings were obtained to monitor the latency to first electrographic seizures and to first status epilepticus induced by intraperitoneal injection of pilocarpine(200mg/kg). Data were analyzed using the log-rank test. RESULTS: Electrographic seizures and status epilepticus were seen in 80% of vigabatrin-treated group, and in 100% of control group rats. And the latency to first seizure was 8.8+/-2.0 minutes in control group and 20.5+/-5.2 minutes in vigabatrin-treated animals(P<0.02), and to status epilepticus was 12.2+/-1.2 minutes in control group and 29.3+/-6.3 minutes in vigabatrin-treated group(P<0.03). CONCLUSION: It was confirmed that 30mg/kg of vigabatrin administration for 6 days did not affect the body weight gain and behavior of immature rats and had an anticonvulsant effect. These findings might demonstrate that the prolonged latency to seizure, and to status epilepticus, was a time to reduce GABA that was elevated in the brain by vigabatrin administration below the seizure threshold, by pilocarpine.
Subject(s)
Animals , Rats , Body Weight , Brain , Electrodes , Electroencephalography , gamma-Aminobutyric Acid , Injections, Intraperitoneal , Pilocarpine , Rats, Sprague-Dawley , Seizures , Status Epilepticus , VigabatrinABSTRACT
PURPOSE: Acute administration of non-selective serotonin (5-HT) reuptake inhibitor such as imipramine and selective 5-HT reuptake inhibitor, like fluoxetine leads, to an increase of extracellular 5-HT concentration in the brain. We sought to determine the average time spent asleep, the frequency of REM sleep, and the percent of REM and NREM sleep in the total sleep time in saline (sham-treated control) (n=6), imipramine (n=8), or fluoxetine (n=6)-treated animals. METHODS: Right and left cortical and hippocampal electrodes were placed in 10-15 day old Sprague-Dawley rats. The following day 2 hour video EEG recordings were done to monitor sleep induced by intraperitoneal injection of saline, imipramine (10mg/kg), or fluoxetine (10mg/kg) after getting a baseline EEG during 30 minutes. And data were analyzed using t-test. RESULTS: 1) Following intraperitoneal injection of saline, imipramine, or fluoxetine, there were no epileptiform features or changes in the EEG except for a difference in sleep cycling. 2) The percent of average time spent asleep was significantly greater for control (87.8%) and fluoxetine-treated animals (92%) compared to imipramine-treated animals (66.1 %) (p<0.005). 3) The average frequency of REM sleep was 11.2 in control, 0.1 in imipramine-treated animals, and 8.7 in fluoxetine-treated animals, respectively during the 2 hours. And the frequency of REM sleep was significantly less for imipramine-treated animals compared to control (p<0.002). 4) Control animals (41.2%) spent significantly less time in NREM sleep compared to imipramine (98.8%)- and fluoxetine (93%)-treated animals (p<0.0001) and significantly more time (58.8%) in REM sleep compared to both imipramine (1.2%)- and fluoxetine (7%) treated animals (p<0.0001). CONCLUSION: We confirmed that postnatal 10-15 day old rats spent more time in REM sleep than NREM sleep, and acute administration of imipramine or fluoxetine increased NREM sleep by decreasing the frequency and the duration of REM sleep by 5-HT reuptake inhibition in the brain.