不同强度耐力训练后大鼠骨骼肌酶活性适应性变化的研究

为探讨不同强度耐力训练对大鼠腓肠肌 (SO纤维 )和股四头肌深层 (FOG纤维 )中氧化酶与糖酵解酶活性变化的影响 ,采用 2 6米 /分、30米 /分、36米 /分和 4 2米 /分的训练强度对大鼠进行了 16周跑台耐力训练 ,并用生化和组化的方法分别测定腓肠肌MDH、PFK和LDH活性和股四头肌深层的SDH和LDH活性的变化。结果表明 :不同强度的耐力训练后大鼠SO和FOG纤维的MDH、SDH活性变化出现了不同的适应性变化 ,并且中等强度的训练对氧化酶的发展最有效。另外 ,PFK、LDH活性在不同强度的耐力训练后不变或降低。     

2周耐力训练削弱骨骼肌5′-一磷酸腺苷激活的蛋白激酶信号对急性运动的反应

目的:探讨2周耐力训练对大鼠一次急性运动骨骼肌5′-一磷酸腺苷激活的蛋白激酶(AMPK)信号的影响,分析骨骼肌AMPK信号对耐力训练的适应特点。方法:52只雄性SD大鼠分为训练和未训练两大组,训练组进行2周速度为18m/min、10%坡度、每天60min的耐力训练,结束后进行一次性大强度跑台运动(速度26m/min,10%坡度,60min);未训练组只进行一次性大强度跑台运动。两组分别于一次性运动前(安静时)、运动后即刻(0h)、1h和6h取材。使用高效液相色谱法(HPLC)测定AMP、ATP含量,放射性同位素方法测定AMPK活性。结果:与安静时相比,训练和未训练组大鼠一次性运动后即刻,腓肠肌AMP、AMP/ATP、AMPK分别增加42%、80%、80%和62%、89%、180%,均有统计学意义(P<0.01),AMP和AMP/ATP在运动后1h恢复,AMPK在运动后6h恢复;和未训练组相比,训练组一次性运动后即刻AMP和AMPK的增幅分别下降20%(P<0.05)和100%(P<0.01),但两组ATP和AMP/ATP在各时间点均无显著差异。结论:2周耐力训练削弱骨骼肌AMPK对急性运动的反应,其原因可能与AMP含量的增幅被削弱有关。     

耐力训练与心脏内分泌研究之二——不同强度、不同量耐力训练后大鼠心房超微结构的改变

对不同强度、不同量耐力训练后心房肌细胞及其毛细血管进行了电镜观察,从亚细胞水平初步探讨运动心脏超微结构的改变。     

低氧训练对大鼠骨骼肌VEGF mRNA表达及毛细血管密度的影响

目的:探讨低氧训练对大鼠骨骼肌血管内皮细胞生长因子(VEGF)mRNA水平表达及毛细血管密度的影响.方法:选用6周龄雄性SD大鼠120只,经3周适应性训练和力竭实验筛选出90只,随机分为9组:常氧安静对照组、持续低氧安静组、间歇低氧安静组、低住低练组、高住高练组、高住低练组、低住高练组、高住高练后复氧训练组、高住低练后复氧训练组.采用常压低氧舱以13.6%的氧浓度(相当于海拔3500m的氧浓度)作为低氧环境,根据血乳酸一速度曲线确定大鼠常氧训练的强度为35m/min,低氧训练的强度为30m/min.低氧训练持续时间为6周,每周训练5天.在第6周末的最后一次运动后休息48小时后处死大鼠并取材.采用实时荧光定量PCR技术、免疫组化染色法检测大鼠骨骼肌VEGF mRNA表达及毛细血管密度.结果:与常氧安静对照组相比,高住高练组骨骼肌VEGF mRNA表达明显提高(P＜0.01),而高住低练组和低住高练组变化不明显;高住高练后复氧训练l周,大鼠骨骼肌VEGF mRNA表达有非常显著性下降(P＜0.01),回到常氧安静组水平.与常氧安静对照组相比,高住高练组和低住高练组骨骼肌毛细血管密度增加,有非常显著性差异(P＜0.01).结论:(1)高住高练比高住低练和低住高练更能显著提高骨骼肌VEGFmRNA表达水平.(2)低氧-常氧的反复刺激更有利于血管生成.低氧下训练比常氧下训练更有利于提高骨骼肌毛细血管密度.低住高练和高住高练对血管生成的效果好于高住低练.     

2周耐力训练削弱骨骼肌5''-一磷酸腺苷激活的蛋白激酶信号对急性运动的反应

目的:探讨2周耐力训练对大鼠一次急性运动骨骼肌5'-一磷酸腺苷激活的蛋白激酶(AMPK)信号的影响,分析骨骼肌AMPK信号对耐力训练的适应特点.方法:52只雄性SD大鼠分为训练和未训练两大组,训练组进行2周速度为18m/min、10%坡度、每天60min的耐力训练,结束后进行一次性大强度跑台运动(速度26m/min,10%坡度,60min);未训练组只进行一次性大强度跑台运动.两组分别于一次性运动前(安静时)、运动后即刻(0h)、1h和6h取材.使用高效液相色谱法(HPLC)测定AMP、ATP含量,放射性同位素方法测定AMPK活性.结果:与安静时相比,训练和未训练组大鼠一次性运动后即刻,腓肠肌AMP、AMP/ATP、AMPK分别增加42%、80%、80%和62%、89%、180%,均有统计学意义(P<0.01),AMP和AMP/ATP在运动后1h恢复,AMPK在运动后6h恢复;和未训练组相比,训练组一次性运动后即刻AMP和AMPK的增幅分别下降20%(P<0.05)和100%(P<0.01),但两组ATP和AMP/ATP在各时间点均无显著差异.结论:2周酎力训练削弱骨骼肌AMPK对急性运动的反应,其原因可能与AMP含量的增幅被削弱有关.     

耐力训练对大鼠骨骼肌超微结构及IGF-1表达影响的研究

目的探讨大鼠骨骼肌对中等负荷耐力训练的适应性变化。方法40只雄性Wiser大鼠进行上坡跑中等负荷运动，观察不同训练阶段大鼠比目鱼肌的超微结构和IGF-1表达的变化。结果组织病理学观察示大鼠比目鱼肌发生了运动性肌肉损伤，且在第3周时损伤最重，出现骨骼肌结构相对“薄弱期”。同时，肌组织中IGF-1水平明显升高。肌组织在损伤后即开始自行修复，运动4周后，Z线异常率和IGF-1水平逐渐降低，病理改变逐渐减轻。结论肌肉损伤有一个逐渐加重后经修复逐渐减轻的过程，说明在损伤积累的同时，肌肉表现出良好的适应能力。     

不同强度不同时间耐力训练对于大鼠心肌细胞自噬发生程度的影响

目的:探讨不同强度不同时间耐力训练对大鼠心肌细胞自噬程度的影响,为运动强度和时间对心肌细胞自噬发生机制的探讨提供依据。方法:选用48只健康成年雄性SD大鼠,随机分为安静对照组、中等强度训练组和大强度训练组,每组16只。分别以15.2 m/min速度5°坡度和28 m/min速度10°坡度进行跑台训练,每周训练5天,每次训练1小时。于第8周和16周分别取各组大鼠8只进行体重称量、超声心动图检测,计算心脏重量指数(HWI);取左心室壁用于HE染色,观察心肌组织形态;制备超薄切片进行透射电镜观察,检测自噬发生程度。结果:运动训练16周后,大强度组HWI显著低于同期对照组及同组训练8周后(P<0.05)。超声心动图显示,训练8周后,中等强度组EF值显著高于同期对照组(P<0.05);训练16周后,中等强度组LVPWD、LVPWS、EF均显著高于同组训练8周后,大强度组EF值显著低于同期对照组(P<0.05)。HE染色结果显示,大强度组心肌细胞损伤严重。透射电镜检测显示,长时间大强度耐力训练使自噬小体增多,自噬程度增加。结论:耐力训练可引起心肌组织细胞良好的适应性重塑,但大强度长时间耐力训练会导致心肌纤维形态异常,线粒体损伤聚变,自噬体增多等病理现象,构成心肌损伤的结构基础。     

耐力训练后大鼠心肌毛细血管的研究之一——毛细血管显微形态计量研究

本文对耐力训练的实验大鼠心肌毛细血管结构进行了体视学形态计量分析。提示经适宜负荷耐力训练后,与心肌组织细胞供氧有关的毛细血管结构产生了良好的适应性变化,有利于运动心脏的功能。     

耐力训练后大鼠心肌毛细血管的研究之二——毛细血管ATP_(ase)、AKP活性、超微结构及密度的改变

本文对经过上、下坡跑台耐力训练的大鼠心肌毛细血管进行了研究,结果表明,毛细血管壁上ATP_(ase)、AKP活性反应增强;毛细血管密度(CD)和毛细血管与心肌纤维的比值(C/F)增高;毛细血管内皮细胞胞浆中微饮小泡增多,毛细血管腔面微绒毛状结构增多。两种训练方式下左、右心室毛细血管的改变基本一致。提示,耐力训练后心肌毛细血管产生了良好的适应性变化,有利于运动心脏的血液供应。     

高强度间歇训练对老龄大鼠骨骼肌减少症及某些氧化应激、脂肪细胞因子和炎症因子的影响

目的:探讨高强度间歇训练(HIIT)和持续性运动(MICT)对老龄大鼠运动表现、骨骼肌氧化应激、血浆超敏C-反应蛋白(hs-CRP)、白介素-6/10、脂联素和瘦素分泌的影响。方法:48只8月龄SD大鼠适应性喂养2周后进行体成分、耐力和抓力测试,随机选取12只大鼠作为成年对照组,禁食12 h后宰杀;剩下36只大鼠常规饲养10个月,18月龄时进行适应性跑台1周后随机分为三组:老龄安静组、老龄MICT组和老龄HIIT组,每组12只。之后进行8个月跑台训练,老龄MICT组以速度17 m/min进行跑台训练;老龄HIIT组以起始速度15 m/min,时间为4 min,之后跑台速度增至25 m/min,运动1 min,依次交替进行9个循环;两种运动的总时间均为45 min,1次/天,5天/周。末次训练48 h后检测体成分,并进行耐力和抓力测试;耐力测试后48 h禁食12 h宰杀,腹主动脉离心抽取血浆,连同成年对照组,采用酶联免疫吸附试验(ELISA)检测血浆和骨骼肌炎症因子(IL-6、IL-10和hs-CRP)、氧化应激(SOD、MDA、8-OHdG和4-HNE)和脂肪细胞因子(瘦素和脂联素)含量。结果:(1)与成年对照组相比,老龄安静组大鼠的体重、体脂/瘦体重比值和体脂百分比显著增加(P<0.01),瘦体重%、骨骼肌指数、抓力和耐力显著降低(P<0.01),血浆氧化应激、hs-CRP和脂联素均显著增加(P<0.05)。(2)与老龄安静组相比,老龄HIIT组大鼠体脂重量显著减少(P<0.05),瘦体重百分比、耐力、抓力和骨骼肌指数显著增加(P<0.05或P<0.01);老龄MICT组大鼠耐力显著增加(P<0.05)。(3)与老龄安静组相比,老龄HIIT组血浆氧化应激水平(MDA:P<0.05,8-OHdG:P<0.01,4-HNE:P<0.05)、慢性炎症状态(hs-CRP,IL-6/IL-10比值,IL-10)和脂联素水平显著降低(P<0.05),但血浆瘦素显著升高(P<0.05),而老龄MICT组脂联素显著降低(P<0.01);与老龄安静组相比,老龄HIIT组和老龄MICT组骨骼肌SOD2显著升高(P<0.01),8-OHdG(P<0.01)和4-HNE(P<0.05)显著降低;与MICT组相比,HIIT组大鼠骨骼肌8-OHdG (P<0.05)和MDA(P<0.01)显著降低。Pearson相关分析显示,耐力与血浆8-OHdG呈负相关(r=-0.72),血浆hs-CRP与体脂百分比(r=0.55)、MDA(r=0.58)和4-HNE(r=0.66)呈正相关,血浆瘦素与体脂%(r=-0.58)呈负相关。结论:高强度间歇训练可通过调控血浆瘦素水平,改善老龄大鼠体成分,增加骨骼肌指数,提高老龄大鼠运动表现;高强度间歇训练可降低老龄大鼠炎症与氧化应激水平。     

Effect of aerobic exercise training on mtDNA deletion in soleus muscle of trained and untrained Wistar rats

Background: According to the theory of mitochondrial aging, oxidative stress plays a major role in aging and age related degenerative diseases. Since oxygen consumption and reactive oxygen species rate increase during aerobic exercise, we hypothesised that heavy aerobic training could lead to enhanced mitochondrial DNA (mtDNA) deletion in postmitotic tissues, leading in turn to premature aging and degenerative diseases. Methods: Sixty adult male 2 month old Wistar₁₄₈₄₈ rats were divided into six equal groups. Two groups were trained for 3 months by running on a treadmill (5 days/week, incline 6°; group 1: 40 m/min, 20 min/day; group 2: 20 m/min, 40 min/day), while two sedentary groups participated in aerobic exercise only at the end of the study (incline 6°; group 3: 40 m/min; group 4: 20 m/min). To control for physical and physiological parameters, two groups of untrained animals were killed at the beginning (group 6) and end (group 5) of the study. Expand long PCR was used to investigate mtDNA deletion in soleus muscle and a sequencing method was used to confirm the mtDNA deletion break point. Results: Our results did not show any mtDNA deletion in untrained rats or in those that underwent moderate training (group 2) We only found mtDNA deletion (4.6 kb) in the soleus muscle of heavily trained rats (group 1). Conclusions: These results demonstrate that one session of aerobic exercise does not cause mtDNA deletion in skeletal muscle. The difference in results between heavy and moderate aerobic training may be due to low work rate or up-regulation of inducible antioxidant systems in moderate training.     

急性递增负荷跑台运动对小鼠腓肠肌自噬和葡萄糖转运功能的影响

目的:观察急性递增负荷跑台运动对腓肠肌自噬和葡萄糖转运功能的影响,探讨运动激活自噬对骨骼肌葡萄糖转运功能的作用.方法:健康雄性4周龄ICR小鼠适应性喂养3天,然后随机分为安静对照组(Con组,n=6只)和急性递增负荷跑台运动组(n=24只).急性递增负荷跑台运动组小鼠运动力竭后根据恢复时间再分为运动后即刻组(0h组,n...     

不同强度运动时大鼠骨骼肌能量代谢产物的变化

本研究旨在观察不同强度运动时 ,与能量代谢有关的骨骼肌腺嘌呤核苷酸 (ATP)、磷酸肌酸 (CP)、乳酸 (LA)和呼吸链氧化还原的变化特点 ,以进一步阐明训练中运动强度这一重要因素的生理意义。雄性SD大鼠先经 5周耐力训练筛选 ,再进行 3周递增速度训练。正式实验时 ,随机分成 6个强度组 (0m/min、18m/min、30m/min、4 2m/min、5 4m/min、6 6m/min) ,6只 /组 ,每组以 6m/min的增幅进行 3分钟准备活动 (0m/min组为安静时处死 ) ,然后以预定强度跑 3分钟后立即处死 ,取右腿用液氮固定 ,凿取腓肠肌 ,经冷冻干燥后制备肌肉提取液。用高效液相法测定肌肉ATP、ADP、AMP、CP、NADH和NAD+ ,用紫外分光法检测肌乳酸。结果表明 ,随着运动强度的增加 ,运动后即刻大鼠腓肠肌能量代谢产物的变化如下 :(1)ATP浓度在 18～ 4 2m/min范围内呈下降趋势 ,超过 4 2m/min出现上升趋势 ,其中 ,4 2m/min组比安静组降低 (P <0 0 1) ,5 4m/min组较 4 2m/min组升高 (P <0 0 5 ) ;ADP和AMP的变化表现为波动性上升的趋势 ;CP浓度、能荷 (EC)以及ATP/ADP的比值呈波动性下降趋势 ;同时 ,随着ATP/ADP比值的下降 ,AMP的生成增加 ,CP逐渐降解。(2 )肌乳酸、NADH和NADH/NAD+ 比值呈波动性上升趋势 ,当强度大于 4 2m/min时NADH/NAD+明显上升 ,     

+Gz暴露后大鼠海马生长抑素与学习记忆能力变化关系的研究

目的 :探讨 +Gz暴露后大鼠学习记忆能力和海马生长抑素的变化规律。方法 :雄性SD大鼠 80只随机分为对照组、+6Gz/3min组和 +10Gz/3min组 ,观察不同G值 +Gz作用后 ,0、2、4和 6d大鼠学习能力的变化 ,及 +Gz暴露后 0、2和 4d大鼠海马生长抑素 (SS)的变化情况。结果 :Y型迷宫测试中 ,与对照组比较 ,+6Gz/3min组在暴露后 2、4和 6d时正确反应次数均较对照组显著减少 (P <0 .0 1) ,反应时均显著延长 (P <0 .0 1) ;+10Gz/3min组所有正确反应次数均显著减少 (P <0 .0 1) ,反应时均显著延长 (P <0 .0 1) ;与 +6Gz/3min组比较 ,+10Gz/3min组的正确数仅在 0d时显著减少 (P <0 .0 1) ,反应时显著延长(P <0 .0 5 )。放免结果显示 ,与对照组比较 ,+6Gz/3min组和 +10Gz/3min组在暴露后 0、2d海马SS显著降低 (P <0 .0 5或P<0 .0 1)。结论 :+Gz暴露导致大鼠学习记忆能力持续受损 ,海马生长抑素含量降低。     

Interstrain variation in murine aerobic capacity.

PURPOSE: The contribution of genetic factors to aerobic capacity is unknown. The purpose of this study was to measure maximal aerobic performance among inbred strains of mice to provide basic heritability estimates. METHODS: Eight female mice, 8 to 10 wk old, in 10 inbred strains (A/J, AKR/J, Balb/cJ, C(3)H/HeJ, C57Bl/6J, C57L/J, C(3)Heb/FeJ, CBA/J, DBA/2J, and SWR/J) were run on a treadmill until exhaustion. The protocol started at 22 m.min(-1) and increased in speed approximately 6 m.min(-1) every 4 min. After 4 min at 42.4 m.min(-1), the grade was increased 2% every 4 min thereafter until the mouse could not run off of the shock grid (150 V; 1.5 mA). RESULTS: There were significant differences between inbred strains in maximal duration of exercise accomplished (P < 0.0001). The order of strain-specific exercise duration was Balb/cJ > SWR/J > CBA/J > C57L/J > C3H/HeJ > C3Heb/FeJ > C57Bl/6J > AKR/J > DBA/2J > A/J. Two measures of heritability in the broad sense, intraclass correlation (0.73), and the coefficient of genetic determination (0.58) were both significant. CONCLUSION: These data indicate that there is a strong genetic contribution to aerobic capacity in mice.     

Comparative analysis of the Cosmed Quark b2 and K4b2 gas analysis systems during submaximal exercise

AIM: The purpose of this study was to compare the Cosmed K4b2 portable gas analysis system with the Cosmed Quark b2 metabolic cart. METHODS: Twenty-one subjects attended one testing session that consisted of duplicate measurements of gas volumes and concentrations using both Cosmed gas analysis systems at 3 treadmill work rates; 1) 80m x min(-1), 0% grade, 2) 80m x min(-1), 5% grade, and 3) 80m x min(-1), 10% grade. Subjects walked for 3 min at each rate with one of the gas analysis systems attached to the facemask. The order of the procedures was randomized so that one system was used during both phases (1st or 2nd) of each work rate. RESULTS: The results indicated that oxygen consumption (VO2) was significantly higher in the K4b2 compared to the Quark at 80m x min(-1), 0% grade (14.3+/-1.2 vs 13.6+/-1.2ml x kg(-1) x min(-1), respectively), (p<0.01). The fractional concentration of oxygen in expired air was also significantly lower in the K4b2 at 80 m x min(-1), 0% grade and 80 m x min(-1), 10% grade (p<0.05). There were no significant differences between systems for minute ventilation or carbon dioxide production. Despite the small mean bias in mean VO2 values (0.5-1.0ml x kg-1 x min(-1) higher) in the K4b2, all individual values were within the limits of agreement (mean difference+/-2 SD) as determined by the Bland-Altman technique. CONCLUSION: The findings show a minimal bias in respiratory and metabolic parameters during bi-pedal locomotor activities at low to moderate exercise intensities in the two gas analysis systems.     

Minisatellite and Hprt mutations in V79 cells irradiated with helium ions and gamma rays

Purpose : To evaluate and compare cytotoxic and mutational effects of graded doses of γ-rays and 4 He ++ ions at different LET values (nominally 80 and 123 keV/ μ m) in V79 cells. Materials and methods : 4 He ++ ion beams at 80 and 123 keV/ μ m were supplied by the 7 MV Van de Graaff CN accelerator of the INFN-LNL in the dose range 0.3-2.4 Gy at a dose rate of 1 Gy/min. Gamma-irradiation was performed by the 60 Co ' γbeam' of CNR-FRAE (at the INFN-LNL) in the dose range 0.5-6.0 Gy at a dose rate of 1 Gy/min. After irradiation, the cells were seeded to measure surviving fraction (SF) and mutant frequency (MF) at the Hprt locus on the basis of 6-thioguanine resistance. Alterations at minisatellite sequences (MS) of clones derived from irradiated and unirradiated cells were detected by Southern blot analysis using a multi-locus probe (DNA fingerprinting). Results : Survival data from 4 He ++ irradiation at two LET values (80 and 123 keV/ μ m) yielded similar results: α =(1.08 ±0.04)/Gy and (0.90 ±0.03)/Gy, respectively. The best fit for mutant induction at the Hprt locus after 80 keV/ μ m 4 He ++ was a linear function of the dose in the dose-interval 0-1.5 Gy: α =(47.77 ±16.01) ×10 -6 /Gy. The best fit for mutant induction after 123 keV/ μ m 4 He ++ in the dose-interval 0-1.2 Gy was a linear-quadratic function: α =(86.01 ±13.80) ×10 -6 /Gy; β =(42.87 ±11.03) ×10 -6 /Gy 2. For γ-irradiation, the best fit of Hprt mutation data gave: α =(4.14 ±2.67) ×10 -6 /Gy; β =(0.63 ±0.86) ×10 -6 /Gy 2. The best fitting of MS alteration data with linear-quadratic or linear relationships gave: for γ-rays, α =0.56 mutants/Gy and β =0.52 mutants/Gy 2 ; for 80 keV/ μ m 4 He ++, α =3.70 mutants/Gy and β =9.00 mutants/Gy 2 ; for 123 keV/ μ m 4 He ++, α =4.36 mutants/Gy. Conclusions : The results reported here confirmed the higher cytotoxic and mutagenic effects of helium ions in comparison with γ-irradiation and the ability of DNA fingerprint analysis to investigate DNA damage induced by different ionizing radiations. The results of the mutagenic effects measured by the two tests are in agreement.     

高住高练对肥胖大鼠肝脏SREBP-1c表达的影响

目的:探讨高住高练对高脂饮食肥胖大鼠肝脏SREBP-1c表达的影响。方法:出生21天离乳SD雄性大鼠280只,肥胖造模成功后挑选160只,2周适应性训练后筛选130只,随机分为13组:对照组(同时视为低住低练0周组、低氧安静0周组和高住高练0周组),低住低练1、2、3、4周组,低氧安静1、2、3、4周组,高住高练1、2、3、4周组。用水平动物跑台进行有氧耐力运动,低住低练各组在常氧下进行速度为26 m/min、1 h/d、6 d/w的运动,分别持续1～4周;低氧安静各组每天在低氧下(氧浓度为13.6%,约相当于3500 m海拔高度)生活,自由活动,不安排训练,分别持续1～4周;高住高练各组每天在低氧下(氧浓度为13.6%)生活23 h,训练1 h,速度为21 m/min,6 d/w,分别持续1～4周(非训练日生活24 h)。对照组于正式实验开始前、安静组于相应周数后、运动组于最后一次训练后恢复24 h取材。分别采用实时荧光定量PCR技术和Western Blot技术检测大鼠肝脏SREBP-1c基因和蛋白表达。结果:相同训练模式不同周数之间比较,高住高练组大鼠肝脏SREBP-1c mRNA和蛋白表达在第1、2、4周较对照组均变化无统计学意义(P>0.05),第3周mRNA表达降低,与对照组比较差异有统计学意义(P<0.05),第3周蛋白表达下降,与1、2周组之间的差异均有统计学意义(P<0.05)。相同周数不同训练模式之间比较,第1、4周,高住高练组肝脏SREBP-1cmRNA和蛋白表达与低住低练组和低氧安静组比较差异无统计学意义(P>0.05),第2周高住高练组SREBP-1c蛋白表达高于低住低练组(P<0.01),第3周高住高练组SREBP-1c mRNA和蛋白表达低于低氧安静组(P<0.05)。结论:3周高住高练抑制肥胖大鼠肝脏SREBP-1c mRNA和蛋白表达效果较好。     

+Gz暴露后大鼠海马生长抑素与学习能力的变化

目的探讨持续性正加速度( Gz)暴露后,缺血恢复期大鼠学习能力和海马生长抑素的变化规律。方法雄性SD大鼠80只随机分为对照组、 6Gz/3min组和 10Gz/3min组,观察不同G值 Gz作用后,0d、2d、4d和6d大鼠(每组8只)学习能力的变化,及 Gz暴露后0d、2d和4d大鼠海马生长抑素的变化情况(每时间点每组8只)。结果Y型迷宫测试中,与对照组比较, 6Gz/3min组正确反应次数和反应时在0d无显著性改变,在暴露后2d、4d和6d时正确反应次数均较对照组显著减少(P<0.01),反应时均显著延长(P<0.01); 10Gz/3min组在暴露后各时间点的正确反应次数均显著减少(P<0.01),反应时均显著延长(P<0.01);与 6Gz/3min组比较, 10Gz/3min组的正确数仅在0d时显著减少(P<0.01),反应时显著延长(P<0.05),余无显著差异。放射免疫结果显示,与对照组比较, 6Gz/3min组在暴露后0d,2d海马SS显著降低(P<0.05或P<0.01); 10Gz/3min组在暴露后0d,2d时间点海马SS显著降低(P<0.01)。结论 Gz暴露导致大鼠学习能力受损,海马生长抑素含量降低。     

Relationship between Field Strength and Abnormal Development in Chick Embryos Exposed to 50 Hz Magnetic Fields

Summary

Chick embryos were exposed to sinusoidally oscillating 50 Hz magnetic fields during their first 2 days of development. In the first series of experiments magnetic field strengths of 0·1, 0·3, 1 and 10 A/m were used. The percentage of abnormal embryos (%AE) was 16 per cent in the sham-exposed control group. %AE was increased at 1 A/m (29 per cent) and 10 A/m (32 per cent), but not at 0·1 A/m (16 per cent) or 0·3 A/m (14 per cent). In the second series of experiments field strengths of 0·4, 0·6, 0·9 and 1·35 A/m were used. %AE was 17 per cent in the control group, 10 per cent at 0·4 A/m, 19 per cent at 0·6 A/m, 17 per cent at 0·9 A/m and 36 per cent at 1·35 A/m. Only the 1·35 A/m group was significantly different from the controls. The results of this study suggest that exposure of chick embryos to a 50 Hz magnetic field causes abnormal development, and that no abnormalities are induced below a threshold between 0·9 and 1 A/m.