Aerobic exercise improves the inflammatory profile correlated with cardiac remodeling and function in chronic heart failure rats

OBJECTIVE:

The aim of the present study was to evaluate the effect of 8 weeks of aerobic exercise training on cardiac functioning and remodeling and on the plasma levels of inflammatory cytokines in chronic heart failure rats.

METHODS:

Wistar rats were subjected to myocardial infarction or sham surgery and assigned to 4 groups: chronic heart failure trained (n = 7), chronic heart failure sedentary (n = 6), sham trained (n = 8) and sham sedentary (n = 8). Four weeks after the surgical procedures, the rats were subjected to aerobic training in the form of treadmill running (50 min/day, 5 times per week, 16 m/min). At the end of 8 weeks, the rats were placed under anesthesia, the hemodynamic variables were recorded and blood samples were collected. Cardiac hypertrophy was evaluated using the left ventricular weight/body weight ratio, and the collagen volume fraction was assessed using histology.

RESULTS:

The chronic heart failure trained group showed a reduction in left ventricular end-diastolic pressure, a lower left ventricular weight/body weight ratio and a lower collagen volume fraction compared with the chronic heart failure sedentary group. In addition, exercise training reduced the plasma levels of TNF-α and IL-6 and increased the plasma level of IL-10.

CONCLUSION:

An 8-week aerobic exercise training program improved the inflammatory profile and cardiac function and attenuated cardiac remodeling in chronic heart failure rats.     

Postischemic exercise decreases neurogenesis in the adult rat dentate gyrus

Running exercise enhances neurogenesis in the normal adult and aged hippocampus. However, the effect of exercise on neurogenesis in the ischemic hippocampus is unclear. Here, we show that running exercise has different effects on ischemic and non-ischemic brain. Young (3-4-month-old) normotensive Wistar rats were used for this study. We administered bromodeoxyuridine (BrdU) to rats 7 days after the induction of transient forebrain ischemia or sham operation. BrdU-labeled cells were increased in the ischemic subgranular zone (SGZ) and granule cell layer (GCL) and double immunofluoresence showed approximately 80% of BrdU-labeled cells expressed neuronal markers. To assess the effect of running exercise on neurogenesis, BrdU-labeled cells in these regions were quantified after 1 day and 14 days. In sham-operated rats, the numbers of BrdU-labeled cells were significantly increased (2.2-fold) in the SGZ and GCL in response to running exercise. The numbers of BrdU-labeled cells were increased in response to ischemia, however, they were decreased 14 days after BrdU administration and running exercise accelerated the reduction in BrdU-labeled cells in ischemic rats. These findings suggest that running exercise has a negative effect on neurogenesis in the ischemic hippocampus. This may be important with respect to assessment of therapeutic approaches for functional recovery after stroke.     

体力运动和心理应激对大鼠海马去甲肾上腺素和五-羟色胺水平的影响

目的：研究长期体力运动和慢性心理应激对大鼠中枢海马去甲肾上腺素(norepinephrine，NE)和五-羟色胺(serotonin，5-HT)水平的影响，并进一步探讨这2种神经递质在运动减缓应激性海马损伤效应中的作用。方法：采用了4周自愿跑轮运动(运动组)、3周束缚应激（应激组）和预先进行4周运动再施3周应激（运动-应激组）的实验动物模型，高效液相电化学法检测实验大鼠海马的NE和5-HT水平。结果：长期运动大鼠海马的NE和5-HT水平明显升高(P<0.01)，慢性应激大鼠的5-HT水平明显降低（P<0.05）；并且，先运动再应激组的海马NE水平维持正常并显著高于单纯应激组（P<0.01），而以上2组的5-HT水平并无显著差异，且均低于单纯运动组（P<0.05）。结论：在运动益于海马的正性作用中，NE和5-HT可能是重要的调控因素；在应激损伤海马的负性作用中，5-HT可能是重要的调控因素；而在运动减缓应激性海马损伤的作用途径中，NE可能是更重要的调控因素；并且，海马NE可能对运动更敏感，而5-HT可能对应激更敏感。     

Chronic stress impairs learning and hippocampal cell proliferation in senescence-accelerated prone mice

Chronic stress can induce cognitive impairment. It is unclear whether a higher susceptibility to chronic stress is associated with the progression of pathological brain aging. Senescence-accelerated prone mouse 8 (SAMP8) is a naturally occurring animal model of accelerated brain aging. Senescence-accelerated resistant mouse 1 (SAMR1) is usually used as the normal control. In this study, we examined the effects of chronic restraint stress (CRS) on learning in the Y-maze, hippocampal cell proliferation, and the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus of 4-month-old SAMP8 and SAMR1. The results showed that exposure to CRS impaired learning and hippocampal cell proliferation in SAMP8 and SAMR1 but to a much greater extent in SAMP8. Furthermore, CRS significantly decreased the expression of BDNF protein and mRNA in the hippocampus of SAMP8 and SAMR1. These data indicated that SAMP8 is more sensitive to the deleterious effects of CRS on learning than SAMR1. A greater decrease in hippocampal cell proliferation caused by chronic stress may be part of the underlying mechanism for the more severe learning deficit observed in SAMP8. In addition, our findings suggested a role of BDNF in the stress-induced impairment of learning and hippocampal cell proliferation in both strains.     

中药复方SMⅠ对拟老年痴呆小鼠学习记忆能力及海马BDNF表达的影响

目的：探讨中药复方SMⅠ对拟老年性痴呆（AD）小鼠学习记忆能力的影响及其机制。方法：用D-半乳糖腹腔注射62 d和三氯化铝灌胃106 d联合用药制备拟AD动物模型。从造模的第67 d开始，中药组灌胃给中药SMⅠ，连续40 d。给药结束后，通过方形水迷宫、逆转录聚合酶链反应来观察SMⅠ对拟AD模型小鼠学习记忆和脑内脑源性神经营养因子（BDNF）基因表达的影响。结果：SMⅠ可以缩短拟AD模型小鼠水迷宫测试的潜伏期(P<0.01), 减少其错误次数(P<0.05)，同时促进海马BDNF mRNA的表达(P<0.01)。结论：中药复方SMⅠ能提高D-半乳糖和AlCl3拟老年性痴呆小鼠学习记忆能力，其效果优于脑复康。SMⅠ促进学习记忆能力的作用可能与促进BDNF mRNA的表达有关。     

Effects of moderate exercise on cigarette smoke exposure-induced hippocampal oxidative stress values and neurological behaviors in mice

The objective of the present study was to investigate the effects of exercise training on behavior and neurochemical parameters in mice exposed to cigarette smoke. To this aim, mice (C57 BL6) male (30–35 g) were exposed to cigarette smoke 60 consecutive days three times a day and they were subjected to treadmill training 8 weeks for 5 days/week. For behavior assessment, mice were tested in the open-field and forced to a swim test. The superoxide anion, thiobarbituric acid reactive substances and protein carbonyl formation were measured as markers of oxidative stress in hippocampus of mice. In addition, the brain-derived neurotrophic factor (BDNF) levels were measured in the hippocampus samples. Cigarette smoke group and cigarette smoke plus exercise group, increased immobility time in forced swimming test in rats compared to the control group, without affecting spontaneous locomotor activity. There was an increase in the levels of superoxide, TBARS and of protein carbonyl and a decreased in BDNF levels in the hippocampus of rats exposed to cigarette smoke and cigarette smoke plus exercise. Exercise alone did not change any of the parameters evaluated in this study. In conclusion, we observed that physical training improves the oxidative stress parameters, but does not alter depressive-like behavior neither prevent the decreases in BDNF levels in hippocampus induced by cigarette smoke.     

Physical exercise performed before bedtime improves the sleep pattern of healthy young good sleepers

To investigate the influence of different intensities and durations of exercise before bedtime on the sleep pattern and core body temperature of individuals considered good sleepers, we selected 17 healthy males and all underwent 5 nonconsecutive days of study. Measurements of polysomnographic parameters and core body temperature were taken at baseline and after each experimental protocol, performed at night. We found increased sleep efficiency (p = .016) among all protocols compared with baseline data and increase in REM sleep latency (p = .047) between two experiments; there was decrease in the percentage of stage 1 sleep (p = .046) and wake after sleep onset (p = .003). Core body temperature did not change significantly during the nights following exercise. Exercise performed before sleep does not impair sleep quality; rather, its practice improves sleep in good sleepers who are nonathletes, and may be considered to improve sleep pattern.     

In vivo BDNF modulation of adult functional and morphological synaptic plasticity at hippocampal mossy fibers

Brain-derived neurotrophic factor (BDNF) has been proposed as a key regulator and mediator of long-term synaptic modifications related to learning and memory maintenance. Our previous studies show that application of high-frequency stimulation (HFS) sufficient to elicit LTP at the dentate gyrus (DG)-CA3 pathway produces mossy fiber structural modifications 7 days after tetanic stimulation. In the present study, we show that acute intrahippocampal microinfusion of BDNF induces a lasting potentiation of synaptic efficacy in the DG-CA3 projection of anesthetized adult rats. Furthermore, we show that BDNF functional modifications in synaptic efficacy are accompanied by a presynaptic structural long-lasting reorganization at the hippocampal mossy fiber pathway. These findings support the idea that BDNF plays an important role as synaptic messenger of activity-dependent synaptic plasticity in the adult mammalian brain, in vivo.     

Aerobic exercise training and cardiovascular reactivity to psychological stress in sedentary young normotensive men and women

Forty-five (22 women) sedentary young (18-30 years old) nonsmoking normotensive volunteers engaged in either 6 weeks of aerobic training (AT), weight training (WT), or a no-treatment (NT) condition to determine whether AT lowers systolic (SBP) and diastolic (DBP) blood pressure, heart rate (HR), and rate-pressure product (RPP) during rest, psychological stress, and recovery periods. Estimated VO(2)max increased for the AT (32.1+/-1.1 to 38.4+/-1.0 ml.kg(-1).min(-1)). A smaller increase for the WT (30.5+/-1.1 to 33.8+/-1.0) was likely due to increased leg strength, and VO(2)max did not change for the NT (32.5+/-1.1 to 32.9+/-1.0). Heart rate and RPP levels were lower during psychological stress and recovery after training for AT relative to the WT and NT. Overall SBP was also lower in the AT relative to the NT but not the WT. In conclusion, aerobic training lowered cardiovascular activity levels during psychological stress and recovery in healthy young adults, implying a protective role against age-related increases in coronary heart disease for individuals who adopt aerobic exercise early in life and maintain the behavior across the life span.     

Effects of short-term endurance exercise training on vascular function in young males

We investigated effects of 6 days of endurance exercise training [cycling at 65% of peak oxygen consumption (VO_2peak) for 2 h a day on six consecutive days] on vascular function in young males. Measures of VO_2peak, arterial stiffness, calf vascular conductance and heart rate variability were obtained pre- and post-training. Indices of arterial stiffness were obtained by applanation tonometry to determine aortic augmentation index normalized to a heart rate of 75 bpm (AI _x @75 bpm), and central and peripheral pulse wave velocity (CPWV, PPWV). Resting and maximal calf vascular conductances were calculated from concurrent measures of blood pressure and calf blood flow using venous occlusion strain-gauge plethysmography. Time and frequency domain measures of heart rate variability were obtained from recording R–R intervals during supine and standing conditions. Both CPWV (5.9 ± 0.8 vs. 5.4 ± 0.8 m/s) and PPWV (9.7 ± 0.8 vs. 8.9 ± 1.3 m/s) were reduced following the training program. No significant changes were observed in AI _x @75 bpm, vascular conductance, heart rate variability or VO_2peak. These data indicate that changes in arterial stiffness independent of changes in heart rate variability or vascular conductance can be achieved in healthy young males following only 6 days of intense endurance exercise.     

大鼠海马结构在空间辨别性学习记忆时的突触形态可塑性的定量研究

目的　观察由空间辩别性学习记忆活动引致的大鼠海马结构的突触可塑性变化。方法　本研究继电子显微镜下 ,对空间辨别性学习记忆模型大鼠和对照大鼠海马结构内突触形态学的对比性观察之后 ,又对两组大鼠海马结构内突触复合体进行了体视学指标的测算。结果　模型组大鼠海马CA3区多形层内突触数密度 (77 81± 16 0 0 )个 / μm3、突触活性点膜面积 (0 0 37± 0 0 0 8) μm2 / μm3、突触小泡的数量 (16 9946 86± 195 92 5 8)个 / μm3、线粒体的体积 (1 70± 0 86 ) %和数密度 (8777 5 4± 2 0 2 0 32 )个 / μm3 均比对照组大鼠的大或多 ,对照组大鼠以上指标分别为 :(2 8 35± 1 31)个 / μm3、(0 0 15± 0 0 0 2 ) μm2 /μm3、(6 4380 2 7± 872 8 6 6 )个 / μm2 、(0 5 8± 0 35 ) %、(2 2 82 46± 72 7 6 9)个 / μm3,其差异有高度显著性 (P <0 0 1)。结论　正常生理活动也可引致神经发生突触可塑性变化 ;突触可塑性变化的形式不仅包括突触复合体各结构的增大同时包括突触数量增多 ;突触活性点膜面积增大 ;突触小泡的数量增多和体积增大 ;突触前膨大内线粒体数量增多和体积增大。     

Maternal treadmill exercise during pregnancy decreases anxiety and increases prefrontal cortex VEGF and BDNF levels of rat pups in early and late periods of life

In a previous study we demonstrated that, regular aerobic exercise during pregnancy decreased maternal deprivation induced anxiety. The purpose of this study is to investigate whether the positive effects of maternal exercise on the male and female offspring's early and late period of life. Half of the test subjects in each group were evaluated when they were 26 days old, and the other half were evaluated when they were 4 months old. The anxiety levels of maternally exercised groups were less than the control groups in both sexes and in both prepubertal and adult periods. The locomotor activity more increased in females. The prefrontal VEGF and BDNF levels were greater for both age groups and sexes in the maternally exercised group compared to control group. Moreover, there was a strong positive correlations between prefrontal cortex BDNF levels and results of open field tests; and VEGF levels and results of elevated plus maze tests. There was no difference in serum corticosterone levels between groups. These results indicate that maternal exercise during pregnancy may protect the pups from anxiety in early and late periods of life, and affects the prefrontal cortex positively.     

卵巢移植对去势大鼠海马神经元形态及BDNF表达的影响

目的:观察卵巢移植后大鼠海马神经元形态变化及BDNF的表达,评价卵巢移植对海马神经元的保护效果。方法:制作去势SD大鼠模型,卵巢移植干预组在其肾被膜下移植出生3 d内的SD乳鼠卵巢,外源性激素干预组隔天给予腹腔注射乙烯雌酚1 mg/kg。分别于干预后的4、7、14和28 d,电镜观察海马神经元形态及免疫组化观察BDNF的表达情况。结果:卵巢移植后随着移植时间的延长血清雌激素和孕酮水平都逐步升高,乙烯雌酚组仅雌激素水平升高;各组海马神经元形态逐渐好转,移植14 d和28 d组海马神经元的形态改善优于同期给药组。卵巢移植组和乙烯雌酚组BDNF的表达在各区均有所升高,卵巢移植14 d和28 d组CA3区尤为明显(P<0.05)。结论:卵巢移植可以恢复卵巢内分泌功能,对海马神经元形态有改善作用及促进BDNF的表达,其神经元保护作用优于单纯乙烯雌酚干预组。     

Influence of acute submaximal exercise on T-lymphocyte suppressor cell function in healthy young men

A defect in T-lymphocyte suppressor cell function has been reported to occur in a number of autoimmune diseases. The influence of exercise on suppressor cell function has not been determined in individuals with autoimmune diseases, nor has it been determined in healthy individuals. The purpose of this investigation was to determine the effect of an acute bout of submaximal exercise on suppressor cell function in healthy males. Each subject (n=10) completed an exercise trial (E; 1 h of cycle ergometry at 70.6% of maximal oxygen uptake, followed by 2 h of recovery) and a resting trial (R; 3 h of seated rest), separated by at least 1 week. Treatment (E or R) order was counterbalanced. Venous blood samples were obtained pre-exercise (PRE), immediately after exercise (POST), and 2 h post-exercise (2HPOST), and at the same time points in the R trial. Lymphocyte phenotype percentages were determined by flow cytometry, while concanavalin- A-induced suppressor cell function was determined on peripheral blood mononuclear cells. No change was observed in the percentage of T-cytotoxic/suppressor cells. Suppressor cell function was significantly different between treatments, with the POST E value [mean (SD) 56.8 (1.6)%] being higher than the POST R value [41.7 (1.9)%]. No significant difference was observed 2HPOST. In conclusion, acute submaximal exercise resulted in a transient increase in suppressor cell function in healthy males. Accepted: 17 January 2000     

Physical exercise increases adult hippocampal neurogenesis in male rats provided it is aerobic and sustained

Key points

• Aerobic exercise, such as running, enhances adult hippocampal neurogenesis (AHN) in rodents.
• Little is known about the effects of high‐intensity interval training (HIT) or of purely anaerobic resistance training on AHN.
• Here, compared with a sedentary lifestyle, we report a very modest effect of HIT and no effect of resistance training on AHN in adult male rats.
• We found the most AHN in rats that were selectively bred for an innately high response to aerobic exercise that also run voluntarily and increase maximal running capacity.
• Our results confirm that sustained aerobic exercise is key in improving AHN.

Abstract

Aerobic exercise, such as running, has positive effects on brain structure and function, such as adult hippocampal neurogenesis (AHN) and learning. Whether high‐intensity interval training (HIT), referring to alternating short bouts of very intense anaerobic exercise with recovery periods, or anaerobic resistance training (RT) has similar effects on AHN is unclear. In addition, individual genetic variation in the overall response to physical exercise is likely to play a part in the effects of exercise on AHN but is less well studied. Recently, we developed polygenic rat models that gain differentially for running capacity in response to aerobic treadmill training. Here, we subjected these low‐response trainer (LRT) and high‐response trainer (HRT) adult male rats to various forms of physical exercise for 6–8 weeks and examined the effects on AHN. Compared with sedentary animals, the highest number of doublecortin‐positive hippocampal cells was observed in HRT rats that ran voluntarily on a running wheel, whereas HIT on the treadmill had a smaller, statistically non‐significant effect on AHN. Adult hippocampal neurogenesis was elevated in both LRT and HRT rats that underwent endurance training on a treadmill compared with those that performed RT by climbing a vertical ladder with weights, despite their significant gain in strength. Furthermore, RT had no effect on proliferation (Ki67), maturation (doublecortin) or survival (bromodeoxyuridine) of new adult‐born hippocampal neurons in adult male Sprague–Dawley rats. Our results suggest that physical exercise promotes AHN most effectively if the exercise is aerobic and sustained, especially when accompanied by a heightened genetic predisposition for response to physical exercise.

Abbreviations

AHN

adult hippocampal neurogenesis

BDNF

brain‐derived neurotrophic factor

BrdU

bromodeoxyuridine

HIT

high‐intensity interval training

HRT

high‐response trainer

LRT

low‐response trainer

RW

running wheel

Sed

sedentary

TBS

Tris‐buffered saline

V˙O2max

maximal oxygen uptake

     

Effects of interference on discrimination learning and recall by rats with hippocampal lesions

The performance of rats with hippocampal, cortical, or sham lesions on a visual pattern discrimination task was examined under various interference conditions. In Experiment 1, all groups learned the discrimination within normal limits but the hippocampal group was impaired in a retention test if a high interference task involving similar stimulus material was introduced between original learning and retesting. In Experiment 2, animals with hippocampal lesions were similarly impaired in the initial acquisition of the discrimination habit when the high interference task was introduced prior to the beginning of training. The results were related to similar deficiencies in human amnesics with known or suspected hippocampal damage and were interpreted as reflecting a basic inability to use available cues to dissociate competing experiences.     

急、慢性应激对大鼠海马BDNF表达的时序性影响

 摘要：目的 观察急性应激和重复低强度强迫游泳应激后大鼠海马BDNF及BNDF mRNA在不同时间点的动态表达;观察慢性应激条件下动物行为改变。方法 采用反转录－聚合酶链反应（RT-PCR）方法,观察急性和慢性应激对大鼠海马BDNF mRNA的动态表达的影响;采用Western bloting方法检测海马BDNF 蛋白表达量的变化。结果 急性应激导致动物海马BDNF mRNA及其产物表达增加,3小时后表达逐渐降低,与对照组比较差异具有显著性;慢性应激后BDNF蛋白表达呈降低趋势,并在多时点显著低于急性应激组 (p<0.05)。结论 急性应激显著增强大鼠海马BDNF表达;慢性应激组大鼠BNDF mRNA表达存在一定适应现象,且多时点表达量显著低于急性应激组。     

High-intensity intermittent running training improves pulmonary function and alters exercise breathing pattern in children

We investigated the effects of short duration running training on resting and exercise lung function in healthy prepubescent children. One trained group (TrG) (n = 9; three girls and six boys; age = 9.7 ± 0.9 year) participated in 8 weeks of high-intensity intermittent running training and was compared to a control group (ContG) (n = 9; four girls and five boys; age = 10.3 ± 0.7 year). Before and after the 8-week period, the children performed pulmonary function tests and an incremental exercise test on a cycle ergometer. After the 8-week period, no change was found in pulmonary function in ContG. Conversely, an increase in forced vital capacity (FVC) (+7 ± 4% ; P = 0.026), forced expiratory volume in one second (+11 ± 6% ; P = 0.025), peak expiratory flows (+17 ± 4% ; P = 0.005), maximal expiratory flows at 50% (+16 ± 10% ; P = 0.019) and 75% (+15 ± 8% ; P = 0.006) of FVC were reported in TrG. At peak exercise, TrG displayed higher values of peak oxygen consumption (+15 ± 4% ; P<0.001), minute ventilation (+16 ± 5% ; P = 0.033) and tidal volume (+15 ± 5% ; P = 0.019) after training. At sub-maximal exercise, ventilatory response to exercise was lower (P = 0.017) in TrG after training, associated with reduced end-tidal partial oxygen pressure (P<0.05) and higher end-tidal partial carbon dioxide pressure (P = 0.026). Lower deadspace volume relative to tidal volume was found at each stage of exercise in TrG after training (P<0.05). Eight weeks of high-intensity intermittent running training enhanced resting pulmonary function and led to deeper exercise ventilation reflecting a better effectiveness in prepubescent children.     

Aerobic fitness and body fat of young British males entering the army

Summary Aerobic fitness and percent body fat were measured in a sample of 438 male Army recruits between the ages of 17 and 30 prior to the commencement of training. The sample came from all areas of England and Wales. Aerobic fitness, as represented by maximal oxygen uptake ( O₂ max), was predicted from the Astrand submaximal bicycle heart rate test. Body fat was predicted from four skinfold measurements. Total group means ±SD were: age, 19.5±2.5 years; O₂ max 41.7 ±8.3 ml/kg·min; and body fat, 14.5±4.8% of body weight. O₂ max varied with age, athletic participation and aptitude score. No relationship was found with occupation of parent, prior civilian occupation or smoking severity. When adjusted for methodological differences, O₂ max was slightly below similar Army entrants in Norway and the United States.