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Objective To investigate effects of physical exercise (PE) on object recognition memory in adult rats of postnatal isoflurane (Iso) exposures.Methods One hundred and ten postnatal 7-day SD rats (P7) were randomly divided into four groups: normal control group (Naive), Naive+PE group (received physical exercise in P21: a treadmill exercise 30min each day, 5 times/week, for 6 weeks), Iso group (three times of 2-hour Iso exposure in P7, P9, and P11), and Iso+PE group (received PE in P21 after postnatal Iso exposures). In P67, behavioral testing was conducted including open field and object recognition task (ORT), recording the time (Discrimination Ratios, DR) that rats spent on exploring each object, evaluating effects of PE on object recognition memory.Results There was no significant difference in influence of PE on open field testing in all of the groups (P>0.05). Compared with Naive, there was no group difference in DR (P>0.05) for all groups, but the DR of Iso male rats was significantly higher than that of Naive female rats in P67, with significant difference (P=0.034). Compared with non-PE groups, whether or not postnatal Iso exposures, the DR of PE male groups was significantly higher (compared with Naive and Iso group:P67,P=0.050,P=0.017; P95,P=0.037,P=0.019); in female rats, the DR for ISO+PE group was lower than that of Iso group in P67 (P=0.036), but the DR of Naive+PE group was higher than that of Naive group in P95 (P=0.004). Compared with male rats, the DR of non-PE female rats was significantly higher in P67 (vis. Naive and Iso group:P=0.022,P=0.011); but in P95, the DR of non-Iso female groups was significantly higher than that of male groups (vis. Naive and Naive+PE:P=0.008,P=0.017).Conclusions There is no obvious impact of postnatal Iso exposures on object recognition memory of adult rats. These Results also indicate that postnatal PE could improve object recognition memory of non-spatial learning in adult rats. In addition, exercise benefits have gender differences.
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Objective To investigate the potential effect of glucagon-like peptide-1 (GLP-1) analogue exendin-4 (Ex-4) on immune function of T lymphocytes via neuroendocrine modulation mechanism in mice following severe burns.Methods Male BALB/C mice were randomly (ramdam number) divided into thermal injury group (n =50) and sham-thermal group (n =30).The thermal injury model was made by exposing the back skin of 15％ total body surface area (TBSA) to 95 ℃ water for 7 seconds,while in sham-thermal model the mice were immersed in 37 ℃ water instead.The expression of GLP-1 receptor (GLP-1 R) was determined in sorted CM + T cells from normal mice by immunofluorescence method.In ex vivo experiment,the mice were sacrificed at 24 h post-bum,then the mononuclear cells (MNC) from spleen were separated from both groups and cultured in RMPI 1640 with 10％ FCS (fetal calf serum) in presence of ConA (concanavalin A,5 μg/mL).Cells were pretreated with catecholamine receptor antagonist propranolol (prop) for 1 hour,followed by consecutive dose of Ex-4 for another 48 h.In in vivo experiment,prop (30 mg/kg) was i.p.injected 30 minutes before thermal injury,then Ex-4 (2.4 nmol/kg) was injected i.p.immediately after scalding.Mice were sacrificed at 6 h and 24 h after thermal injury,then the serum and the spleens were collected.Results GLP-1R was expressed on splenic CD4 + T cells from normal micc.Ex-4 exerted no marked effect on the functions of T cells in terms of proliferation and IL-2 secretion at all doses examined ex vivo,which was not affected by pretreatment with prop.In vivo,T cell functions were suppressed by Ex-4 in thermal mice (P ＜ 0.05),but was restored by pretreatment with prop.Regardless of ex vivo or in vivo,Ex-4 could induce T cells switched to Th2 response (P ＜ 0.05).Moreover,the Th2 switch by Ex-4 was greatly potentiated by prop intervention in thermal mice in vivo other than ex vivo.Norepinephrine level was increased and epinephrine was decreased by Ex-4 in thermal mice.Both norepinephrine and epinephrine levels were obviously enhanced by pretreatment with prop.Conclusions Ex-4 can inhibit the proliferation and IL-2 secretion of splenic T lymphocytes through the sympathetic nervous system,however,it might induce Th2 switch from Th cells by acting directly on GLP-1R.
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Objective To investigate effects of isoflurane anesthesia of different time interval on acute injury of brain function in neonatal rats with consistent total time of isoflurane anesthesia. Methods Seven-day neonatal Sprague-Dawley (SD) rats were randomly divided into normal control group (breathe the air), continuous anesthesia group (a single 6-hour exposure to 1.5% isoflurane), and intermittent anesthesia 1 day and 3 days groups (three times of 2-hour exposure to anesthesia with an interval of 1 day or 3 days), 12 rats in each group. The ratio of male to female was 5:7. They underwent the test of learning and memory in the radial arm maze (RAM) 21 days after birth, twice a day for 4 days. The number of entry into wrong arms, number of repeated errors, number of total arm entries, and time for completing the task were recorded for evaluation of effect of neonatal isoflurane on cognitive behavior in rats. Results ① Compared with normal control group, the percentage of number of errors > 3 in anesthesia of 3-day interval group was significantly decreased (33.3% vs. 46.9%, P 0 and total arm entries > 8 were significantly increased (33.3% vs. 18.8%, 27.1% vs. 13.5%, both P 3 between continuous anesthesia group, interval anesthesia 1-day group and the normal control group (44.8%, 44.8% vs. 46.9%), the percentages of number of repeated mistake > 0 and total arm entries > 8 in above three groups were slightly increased as compared with those of normal control group (27.1%, 22.9% vs. 18.8%, 20.8%, 21.9% vs. 13.5%, all P > 0.05). No statistical differences in completing the task among normal control group, continuous anesthesia group, interval anesthesia 1 day and 3 days groups were found (minutes: 1.32±0.91, 1.54±1.05, 1.46±0.86, 1.38±0.79, all P > 0.05). ② It was found by gender analysis that the percentages number of repeated errors > 0 and total arm entries > 8 were significantly lower in female rats than those in the male rats only in normal control group (5.0% vs. 28.6%, P 0 in continuous anesthesia group, interval anesthesia 1 day and 3 days groups (25.0%, 25.0%, 30.0% vs. 5.0%, P 8 in interval anesthesia 1 day and 3 days groups were significantly higher than that of normal control group (22.5%, 25.0% vs. 5.0%, both P < 0.05). No significant difference about the RAM task in male rats of all the four groups was found. Conclusions Different time interval of neonatal isoflurane exposure may develop certain degree of acute brain injury in rats, characterized by cognitive function. Prolongation of the interval time significantly enhanced long-term memory in rats. Multiple neonatal exposures to isoflurane were associated with greater cognitive impairment than a single exposure. In addition, isoflurane can significantly increase cognitional functional disorder in the female, not in the male rats.