抗阻训练对增龄大鼠骨骼肌线粒体功能的影响*

目的: 从线粒体动力学的角度,探讨抗阻运动对增龄大鼠骨骼肌线粒体功能的影响。方法: 40只雄性SD大鼠随机分为4组:2月龄安静对照组(C1组)、2月龄抗阻运动训练组(R1组)、6月龄安静对照组(C2组)、6月龄抗阻运动训练组(R2组),每组10只。C1、C2组正常喂养,R1、R2组大鼠进行跑台坡度为35°,速度为15 m/min的抗阻运动,一次跑动15 s,间歇30 s,4次为一组,组间间歇3 min,3组为一次循环,一天为2个循环,循环间歇10 min,每周6 d,共8周。采用Western blot法测定各组大鼠股四头肌线粒体融合蛋白2(Mfn2)、GTP酶1(DRP1) 蛋白含量,使用流式细胞仪测定各组大鼠股四头肌线粒体膜电位(ΔΨm)、活性氧(ROS)和游离钙(Ca²⁺)水平。结果: ① 与C1组相比,R1组大鼠DRP1蛋白升高(P＜0.01)、Mfn2蛋白无显著变化,C2组大鼠DRP1、Mfn2蛋白均降低(P均＜0.01);与C2组相比,R2组大鼠DRP1、Mfn2蛋白均升高(P＜0.01,P＜0.05);与R1组相比,R2组DRP1、Mfn2蛋白均降低(P＜0.01,P＜0.05)。② 与C1组相比,R1组Ca²⁺含量降低(P＜0.01)、C2组Ca²⁺含量升高(P＜0.01);与C2组相比,R2组Ca²⁺含量降低(P＜0.01);与R1组相比,R2组Ca²⁺含量升高(P＜0.01)。③ 与C1组相比,R1组ROS含量有所上升,但无显著性差异,C2组ROS含量升高(P＜0.01);与C2组相比,R2组ROS含量降低(P＜0.01);与R1组相比,R2组ROS含量升高(P＜0.01)。④ 与C1组相比,C2组ΔΨm降低(P＜0.01);与C2组相比,R2组ΔΨm升高(P＜0.01);与R1组相比,R2组ΔΨm有所降低,但无统计学差异。结论: 大鼠增龄过程中股四头肌线粒体出现Ca²⁺堆积、活性氧增多、线粒体膜电位下降、融合蛋白减少等现象,抗阻训练可有效改善这些变化。     

股四头肌腱双束重建前交叉韧带的生物力学特性研究

目的：探讨股四头肌腱的生物力学特性,为其能否应用于临床前交叉韧带（ACL）重建提供实验依据。方法：取32例新鲜尸体的1cm宽股四头肌腱,按其解剖结构分为两束：股直肌、股内、外侧肌腱合为A束,股中间肌腱为B束,用游标卡尺测量两束的宽度及厚度,然后将两束置于电子万能试验机上分别测其生物力学指标。结果：A束厚度为4.39±1.72mm,宽度为8.19±1.18mm,生物力学强度为685.67±227.09N,抗拉强度为17.00±3.48Mpa;B束厚度为3.06±1.47mm,宽度为7.10±2.03mm,生物力学强度为435.04±205.80N,抗拉强度为13.16±4.02Mpa。A束生物力学强度与ACL比较,差异有统计学意义（p〈0.05）;B束生物力学强度与ACL比较,差异有统计学意义（p〈0.05）。结论：股四头肌腱的生物力学性能不能满足ACL双束重建的要求,其在临床上应用于ACL双束重建的价值有待于进一步的深入研究。     

下肢间歇负压疗法对男子赛艇运动员股四头肌皮肤微循环血流灌注量的影响*

目的: 观察下肢间歇负压疗法对男子赛艇运动员股四头肌皮肤微循环血流灌注量的影响,为该方法的实际应用提供理论依据。方法: 选取国家赛艇集训队的14名男子运动员,随机分为试验组和对照组,两组队员每日的训练计划相同,采用德国生产的VACUSPORT间歇负压体能恢复舱对试验组队员实行恢复干预,每次干预20 min,每周干预5次,共持续4周。在4周干预前后利用PeriFlux System 5000激光多普勒血流监测仪采集两组运动员股四头肌皮肤微循环血流灌注量(MBP)、血细胞运动速度(AVBC)及血细胞浓度(CMBC)等数据,测试值包括基础值与加热后值(44℃),并以加热前后的差值作为该指标的储备能力。结果: 干预前两组的微循环相关指标无统计学差异(P＞0.05),4周干预后的测试结果如下①MBP:试验组MBP的加热后值和前后差值均显著高于对照组(P＜0.05);组内比较无统计学差异。②AVBC:试验组AVBC的加热后值和前后差值均显著低于对照组(P＜0.05);组内比较发现,干预后试验组AVBC的加热后值相比干预前显著降低(P＜0.01),其加热前后差值相比干预前显著降低(P＜0.05)。③CMBC:试验组CMBC的加热后值和前后差值均非常显著高于对照组(P＜0.01);组内比较无统计学差异。结论: 下肢间歇负压疗法可改善男子赛艇运动员股四头肌皮肤微循环血流状态,对促进体能的快速恢复有着积极作用。     

Crossing the taxonomic divide: conflict and its resolution in societies of reproductively totipotent individuals

Reproduction in groups may be unequal, with one or a few individuals monopolizing direct reproduction assisted by nonbreeding helpers. In social insects this has frequently led to a pronounced queen-worker dichotomy and a loss of reproductive totipotency among workers. However, in some invertebrate and all vertebrate societies, all or most individuals remain reproductively totipotent. In these groups, conflicts of interest over reproduction are potentially greatest. Here, we synthesize previous analyses of reproductive conflict, aggression and breeder replacement in haplodiploid societies of totipotent individuals and extend them to cover diploid (vertebrate) examples. We test predictions arising from this approach using the best-studied invertebrate (Dinoponera queenless ants) and vertebrate (naked mole-rat, Heterocephalus glaber) examples, although in principle our analysis applies to all similar groups. We find that premature replacement of a parent breeder by nonbreeders (overthrow) is rare. Dominant coercive control of nonbreeders by the breeder is often unnecessary and honest signalling of breeder vitality can maintain group stability and resolve conflicts over reproduction. We hope that by providing an explicit transfer of social theory between ants and naked mole-rats we will stimulate further cross-taxonomic studies that will greatly broaden our understanding of sociality.