Exercise training and experimental diabetes modulate heat shock protein response in brain

In diabetes, defense systems against cellular stress are impaired. Heat shock proteins (HSPs) function primarily as molecular chaperones. Factors that raise tissue HSP levels may slow progression of diabetes and improve diabetic complications that also affect brain tissue. This study tested the effect of an 8-week exercise training on brain HSP response in rats with or without streptozotocin-induced diabetes (SID). In untrained animals, the HSP levels were not different between SID and non-diabetic groups. Endurance training, however, increased HSP72 and HSP90 protein in non-diabetic rats, whereas SID significantly decreased the effect of training on these HSPs. At the mRNA level, HSP60, HSP90 and GRP75 were increased due to training, whereas HSP72 mRNA was only increased in exercise-trained diabetic animals. Training or diabetes had no effect on protein carbonyl content, a marker of oxidative damage. Altogether, our findings suggest that endurance training increases HSP expression in the brain, and that experimental diabetes is associated with an incomplete HSP response at the protein level.     

Effect of induced alkalosis on performance during a field-simulated BMX cycling competition

Objectives

The aim of the present study was to test the effect of sodium bicarbonate (NaHCO₃^?) ingestion on performance during a simulated competition on a Bicycle Motocross (BMX) track.

Suppressed heat shock protein response in the kidney of exercise‐trained diabetic rats

Impaired expression of heat shock proteins (HSP s) and increased oxidative stress may contribute to the pathophysiology of diabetes by disrupted tissue protection. Acute exercise induces oxidative stress, whereas exercise training up‐regulates endogenous antioxidant defenses and HSP expression. Although diabetic nephropathy is a major contributor to diabetic morbidity, information regarding the effect of HSP s on kidney protection is limited. This study evaluated the effects of eight‐week exercise training on kidney HSP expression and markers of oxidative stress at rest and after acute exercise in rats with or without streptozotocin‐induced diabetes. Induction of diabetes increased DNA ‐binding activity of heat shock factor‐1, but decreased the expression of HSP 72, HSP 60, and HSP 90. The inflammatory markers IL ‐6 and TNF ‐alpha were increased in the kidney tissue of diabetic animals. Both exercise training and acute exercise increased HSP 72 and HSP 90 protein levels only in non‐diabetic rats. On the other hand, exercise training appeared to reverse the diabetes‐induced histological changes together with decreased expression of TGF ‐beta as a key inducer of glomerulosclerosis, and decreased levels of IL ‐6 and TNF ‐alpha. Notably, HSP 72 and TGF ‐beta were negatively correlated. In conclusion, impaired HSP defense seems to contribute to kidney injury vulnerability in diabetes and exercise training does not up‐regulate kidney HSP expression despite the improvements in histopathological and inflammatory markers.     

人肝细胞肝癌组织中p53蛋白和热休克蛋白70的表达

目的：进行抗人肝癌的肿瘤主动性免疫研究,初步探讨人肝细胞肝癌（HCC）中p53蛋白及热休克蛋白70（HSP70）的表达并分析其间的关系。方法：免疫组织化学Envision法。结果：p53蛋白及HSP70均定位于细胞核或／和细胞质中。HCC中p53蛋白及HSP70阳性率分别为56．60％及49．06％;p53阳性者中88．68％伴有HSP70阳性,而HSP70阳性者中96．23％同时有p53阳性。结论：HCC中p53蛋白及HSP70表达增高,两者表达间有相关性。     

热休克蛋白70对中暑大鼠急性肺损伤的保护作用及机制研究

目的 观察热休克蛋白70(HSP70)对急性肺损伤的保护作用.方法 64只SD大鼠按随机数字表法分为假加热正常对照组(Sham组)、中暑组(HS组)、中暑加谷氨酰胺处理组(HS+GLN组)和中暑加槲皮素处理组(HS+QU组),每组16只.Sham组大鼠置于温度23℃,湿度55％ ± 5％环境中,其余3组大鼠置于模拟热气候动物舱(舱内温度39℃,相对湿度65％)内.监测大鼠直肠温度、收缩压和脉率,比较各组大鼠热应激反应的差异.以收缩压从峰值开始下降作为中暑的开始,之后将大鼠移至常温复温.分别在中暑恢复期0h和6h处死大鼠,每个时间点8只,留取支气管肺泡灌洗液(BALF)后分离肺脏组织行组织学观察.采用酶联免疫法检测BALF中的IL-1β、TNF-α和IL-6浓度,以及肺组织匀浆中的HSP70浓度.结果 与HS组和HS+QU大鼠比较,HS+GLN组大鼠承受更多的热负荷后才发生HS(P＜0.001),起病后的中位生存时间明显延长(P＜0.001).与Sham组比较,HS组大鼠肺组织匀浆HSP70浓度呈时间依赖性升高(P＜0.001);HS+GLN组HSP70浓度在各个时点与HS组比较均明显升高(P＜0.001),而HS+QU组的HSP70表达则受到明显抑制时点与Sham组比较差异无统计学意义(P＞0.05),但明显低于HS组和HS+GLN组(P＜0.001).与HS组和HS+QU组比较,HS+GLN组大鼠BALF中的IL-1β、TNF-α和IL-6浓度明显降低(P＜0.001),病理结果显示其肺损伤更轻(P＜0.001),而HS+QU组则相反.结论 HSP70具有保护HS大鼠急性肺损伤的作用,其机制可能与增强大鼠热耐受能力和抑制HS大鼠肺部炎症相关.     

The effect of the hyperbaric environment on heat shock protein 72 expression in vivo

Heat shock protein 72 (HSP72) is expressed in response to stress and has been demonstrated to follow a diurnal expression pattern within monocytes and is sensitive to changes in core temperature. Numerous studies have shown changes in HSP72 expression within cell lines exposed to hyperbaric conditions. No studies have investigated changes in HSP72 expression in vivo. Six males participated in the study and were exposed to hyperbaric air and hyperbaric oxygen a week apart. Monocyte HSP72 was analyzed by flow cytometry at 09:00, 13:00, 17:00, 21:00 with hyperbaric oxygen or hyperbaric air breathing commencing at 15:00 for 78 min at a pressure of 2.8 ATA. HSP72 under normoxia followed the established trend; however, following the hyperbaric air or oxygen exposure a reduction in detectable HSP72 was observed at 17:00 and 21:00. No changes in core temperature were observed between 13:00 and 21:00 for any condition. The data show that HSP72 expression is impaired following hyperbaric air (HA) exposure, when compared with control or hyperbaric oxygen (HO) exposure.     

不同+Gz重复暴露下大鼠不同脑区热休克蛋白-70的表达

目的 探讨不同 Gz重复暴露后,大鼠不同脑区热休克蛋白-70（HSP70)表达强度和时程的变化规律。及其与正加速度致脑损伤的相关性。方法 将雄性SD大鼠随机分为对照组、 2Gz、 6Gz和 10Gz暴露组。分别在暴露后6h、1d、2d、4d和6d处死取脑,利用HE和免疫组织化学染色,观察HSP70在鼠脑不同部位的表达。及脑神经元形态学和血脑屏障通透性的变化,结果 G2重复暴露可诱导HSP70的表达。其表达强度,持续时间和部位随G值而异。低G值（ 2Gz)下,表达强度弱,持续时间短,但范围较广;高G值（ 10Gz)下,表达仅局限在下丘脑和梨状皮层等部位。呈中等强度反应;中等强度G值（ 6Gz)下,表达范围广（在皮层、海马、丘脑等部位均有HSP70较强反应）,持续时间长。结论 6Gz诱导的HSP70表达最强,持续时间最长。为研究热休克蛋白对正加速度致脑损伤的保护作用。提供了实验依据。     

离体猪肝胆道内射频消融时毗邻胆道热休克蛋白70表达情况

目的 探讨采用不同功率胆管内射频消融时,毗邻消融靶区的胆管组织热休克蛋白(heat shock protein,HSP)70表达的差异及意义。方法 15个新鲜离体猪肝随机分为3组（胆囊及胆总管中上段完整保留）,将收集的人胆汁注入猪肝胆道系统内,然后将射频消融导管经胆总管引入肝门区胆管内。所有猪肝均消融120 s,第1、2、3组分别采用10 W、12 W、14 W功率消融。消融后取距远端消融电极1cm、2cm处胆管组织,采用免疫组化S-P法检测15例猪肝共30例胆管组织中HSP70的表达。结果 ①距远端消融电极1cm处胆管组织HSP70表达：1级染色4例（26.7%）,2级染色6例（40%）,3级染色5例（33.3%）;距远端消融电极2 cm处胆管组织HSP70表达：1级染色10例（66.7%）,2级染色4例（26.7%）,3级染色1例（6.6%）;②消融区毗邻胆管（距远端消融电极1cm）HSP70表达强度与消融功率呈正相关（r=0.755,P＜0.001）;距远端消融电极1cm、2cm处胆管组织HSP70表达强度差异有统计学意义（Z=-2.334,P＜0.05）。结论 胆管内射频消融可导致消融区毗邻胆管组织HSP70表达,随着消融功率的增加,毗邻消融区胆管组织内HSP70表达强度亦随之增加;远离消融区域胆管（距离远端消融电极≥2cm）HSP70表达无明显增多。     

热休克蛋白70在正常和放射复合伤口愈合血管再生过程中表达及意义研究

目的：探讨HSP70在正常和放射复合伤口愈合过程中表达变化规律及其意义。方法：72只Wistar二级大鼠背部皮肤制作圆形伤口后以25Gy^60Coγ射线局部照射，于伤后2、5、10、15、21、和28d活杀取材，采用LSAB免疫组织化学技术研究HSP70基因表达及意义。结果：单纯创伤组于伤后2d见新生血管内皮细胞浆内15d后，HSP70逐渐减少。创伤＋照射组伤后5d始见血管内皮细胞浆内弱阳性，10－15d时阳性，21天阴性。结论：HSP70参与伤口愈合血管再生的过程，可能对血管再生起促进作用，辐射使血管内皮细胞表达HSP70减少可能是辐射延迟伤口愈合的原因之一。     

Tendinopathy and Doppler activity: the vascular response of the Achilles tendon to exercise

BACKGROUND: Intratendinous Doppler activity has been interpreted as an equivalent of neovessels in the Achilles tendon and as a sign of tendinosis (AT). AIM: To evaluate the vascular response as indicated by color Doppler activity after repeated loading of both symptomatic and non-symptomatic Achilles tendons. MATERIAL AND METHODS: Ten non-trained, healthy subjects ran 5 km. Ultrasound (US) Doppler activity was determined before and after the exercise. Eleven patients with chronic AT performed 3 x 15 heavy-load eccentric exercise. The Achilles tendons were scanned before and immediately after the exercise. RESULTS: Non-symptomatic: six Achilles tendons in five subjects had intratendinous Doppler activity before the exercise. All but two subjects (80%) had intratendinous Doppler activity after running. Symptomatic: all patients had Doppler activity in the tendons, with a median color fraction before eccentric exercise of 0.05 (range 0.01-0.33). The Doppler activity did not disappear after exercise. Tendons with a color fraction below the median at baseline increased significantly after the exercise (P=0.02). CONCLUSION: The mere presence of Doppler in the Achilles tendon does not per se indicate disease. Eccentric exercise does not extinguish the flow during or after one training session in patients with chronic AT.     

Restricting dietary sodium reduces plasma sodium response to exercise in the heat

Exercise‐associated hyponatremia can be life‐threatening. Excessive hypotonic fluid ingestion is the primary etiological factor but does not explain all variability. Possible effects of chronic sodium intake are unknown. The aim of this study was to determine whether dietary sodium affects plasma sodium concentration [Na⁺] during exercise in the heat, when water intake nearly matches mass loss. Endurance‐trained men (n = 9) participated in this crossover experiment. Each followed a low‐sodium (lowNa) or high‐sodium (highNa) diet for 9 days with 24‐h fluid intakes and urine outputs measured before experimental trials (day 10). The trials were ≥2 week apart. Trials comprised 3 h (or if not possible to complete, to exhaustion) cycling (55% VO_2max; 34 °C, 65% RH) with water intake approximating mass loss. Plasma [Na⁺], hematocrit, sweat and urine [Na⁺], heart rate, core temperature, and subjective perceptions were monitored. Urine [Na⁺] was lower on lowNa 24 h prior to (31 ± 24, 76 ± 30 mmol/L, P = 0.027) and during trials (10 ± 10, 52 ± 32 mmol/L, P = 0.004). Body mass was lower on lowNa (79.6 ± 8.5, 80.5 ± 8.9, P = 0.03). Plasma [Na⁺] was lower on lowNa before (137 ± 2, 140 ± 3, P = 0.007) and throughout exercise (P = 0.001). Sweat [Na⁺] was unaffected by diet (54.5 ± 40, 54.5 ± 23 mmol/L, P = 0.99). Heart rate and core temperature were higher on lowNa (P ≤ 0.001). Despite decreased urinary sodium losses, plasma sodium was lower on lowNa, with decreased mass indicating (extracellular) water may have been less, explaining greater heart rate and core temperature. General population health recommendations to lower salt intake may not be appropriate for endurance athletes, particularly those training in the heat.     

The effect of ageing and fitness on thermoregulatory response to high-intensity exercise

There are conflicting reports as to whether ageing causes a decreased thermoregulatory response, or if observed differences in previous studies are related to maximal aerobic capacity or training status. This study hypothesized that thermoregulatory response to severe exercise‐heat stress is maintained with ageing when both young and older subjects are well trained. Seven older highly trained (OHT = 51–63 years) cyclists were matched with two groups of young cyclists (19–35 years); one group matched for training status [young highly trained (YHT) participants, n = 7] and another for [young moderately trained (YMT), n = 7]. Each participant exercised at 70% in hot (35°C, 40% relative humidity) and thermoneutral (20°C, 40% relative humidity) conditions for 60 min. Final rectal temperature in the thermoneutral and heat (YHT = 39.13 ± 0.33°C, YMT = 39.11 ± 0.38°C, OHT = 39.11 ± 0.51°C) tests were similar between all three groups. %HR_max (heat test: YHT = 92.5 ± 6.0%, YMT = 91.6 ± 4.4%, OHT = 88.6 ± 5.1%), skin temperature, and cutaneous vascular conductance during cycling in both environments were similar between groups. Lower sweat loss and evaporative heat loss in the heat test in the OHT and YMT groups when compared with the YHT group reflected lower metabolic heat production. The findings of the present study suggest that thermoregulatory response is maintained with age among highly trained subjects.     

Toward a better prescription of the prone back extension exercise to strengthen the back muscles

This study investigated the level of resistance and the level of muscle activation of the prone back exercise. Fifteen male subjects with no previous history of low back injury performed two repetitions of seven exercises. These consisted of four maximal isometric voluntary contractions (MVC) and three prone back extension (PBE) exercises. The subject was lying prone on a table, the upper body was suspended off the end of the table and the legs and thighs were secured to the table with straps. Three starting positions from the horizontal were investigated, 0 degree, 30 degrees and 60 degrees, and were compared with MVC to quantify the level of effort needed to perform the task. The results showed that the three PBE exercises require a level of resistance and a level of muscle activation generally under 40% of the maximum capacity of healthy subjects. Muscle activity of the erector spinae (ES) was slightly greater when the exercise started at 60 degrees, compared to 0 degree and 30 degrees. During the static phase of the PBE exercises, the level of resistance remained at 40% relative to the peak reaction moment of the MVC, but muscular activity of ES tended to work at a lower activity level. In conclusion, since for healthy subjects PBE exercises are low resistance exercises, they seem to be more specifically designed to develop muscular endurance of the back muscles.     

The response of circulating omentin-1 concentration to 16-week exercise training in male children with obesity

Objectives: The purpose of the present study was to investigate the effects of the 16-week exercise training program on serum omentin-1 in relation to change in insulin resistance in obese male children.

Methods: Thirty-two obese male children, aged 9–12 years, were randomly assigned into Exercise Group (ExG; n = 16) and Control Group (CG; n = 16). ExG participated in a 16-week exercise training program which combined various forms of aerobic activities and resistance training. Body composition, body mass index (BMI), waist circumference (WC), fasting glucose and insulin, homeostasis model assessment estimate of insulin resistance (HOMA2-IR), blood lipids and serum omentin-1 were assessed before and after 16 weeks of training.

Results: Exercise training significantly decreased body mass (7.5%), BMI (7.6%), WC (4.3%), body fat % (15%), fasting insulin (18.5%), total cholesterol (TC) (5.4%), low-density lipoprotein cholesterol (LDL-C) (17%) and triglyceride (TG) (7.4%) compared to CG. Between-groups comparison showed a considerable exercise-induced upregulation in omentin-1 (ES = 89; P < 0.05) levels. Furthermore, in ExG serum omentin-1 levels were significantly increased from 24.5 ± 8.4 to 35.9 ± 9.3 ng/ml (45%; P < 0.001) after the training program, which was accompanied with significantly decreased fasting insulin (P < 0.001). The changes in omentin-1 concentrations correlated with the changes in BMI (r = ?0.67, P < 0.001), WC (r = ?0.62, P = 0.002), body fat % (r = ?0.50, P = 0.004), insulin (r = ?0.65, P = 0.001), HOMA2-IR (r = ?0.60, P = 0.004), TC (r = ?0.53, P = 0.004) and LDL-C (r = ?0.51, P = 0.004) in ExG. BMI (β = ?0.50, P = 0.009) and fasting insulin (β = ?0.54, P = 0.006) changes were found to be independent predictors of omentin-1 increment in multiple regression analysis.

Conclusion: Exercise training resulted in a significant increase in serum omentin-1 concentrations in children with obesity. The ?ndings suggest that exercise-induced changes in omentin-1 may be associated with the bene?cial effects of exercise on reduced insulin and weight lost.     

Effects of carbohydrate beverage ingestion on the salivary IgA response to intermittent exercise in the heat

The purpose of this study was to establish if provision of CHO altered the mucosal immune and salivary cortisol responses to intermittent exercise in the heat. In a double-blind design, 10 males undertook soccer-specific intermittent exercise on a motorized treadmill on 2 occasions, each over 90 min and separated by 1 week. During CHO and placebo trials, subjects were given either a carbohydrate solution (3 ml · kg (-1) body weight) or placebo drink, 5 min before the commencement of exercise, at 15, 30 min, at half time, 60 and 75 min into exercise. Salivary flow rate increased throughout the placebo trial and decreased throughout the CHO treatment; the difference between conditions neared statistical significance (P=0.055). Neither s-IgA concentration nor s-IgA to osmolality ratio was affected by 2 conditions or differed at any time-point post-exercise (P>0.05). The s-IgA secretion rate increased, s-IgA to protein ratio decreased post-exercise and salivary cortisol decreased 24 h post-exercise (P<0.05) compared to pre-exercise. Carbohydrate supplementation whilst exercising in the heat, does not influence rating of perceived exertion, thermal sensation, salivary flow rate, s-IgA concentration, s-IgA secretion rate, s-IgA to osmolality ratio or s-IgA to protein ratio and salivary cortisol but heart rate was increased.     

Differences in the inflammatory plasma cytokine response following two elite female soccer games separated by a 72‐h recovery

We investigated changes in a large battery of pro‐ and anti‐inflammatory cytokines in elite female soccer players following two 90‐min games separated by a 72‐h active or passive recovery. Blood samples were taken from 10 players before, within 15–20 min, 21, 45 and 69 h after the first game and within 15–20 min after the second game. The leukocyte count was analyzed, together with several plasma pro‐ and anti‐inflammatory cytokines, using a multiplex bead array system. After the first and second game, the total leukocytes and neutrophils increased significantly. Likewise, increases (P<0.05) in pro‐inflammatory cytokines [interleukin (IL)‐12, tumor necrosis factor‐α (TNF‐α), interferon‐γ (INF‐γ), IL‐17], chemokines [monocyte chemotactic protein‐1 (MCP‐1), IL‐8 and monokine induced by gamma interferon (MIG)], anti‐inflammatory cytokines (IL‐2R, IL‐4, IL‐5, IL‐7, IL‐10, IL‐13, INF‐α) and the mixed cytokine IL‐6 were observed. Leukocyte and cytokine levels were normalized within 21 h. Active recovery (low‐intensity exercises) did not affect the cytokine responses. A dampened cytokine response was observed after the second game as only IL‐12, IL‐6, MCP‐1, IL‐8 and MIG increased (P<0.05). In conclusion, a robust pro‐ and anti‐inflammatory cytokine response occurs after the first but not the second soccer game. The implications of the dampened cytokine response in female players after the second game are unknown.