Lee Earric, Nissinen Tuuli A, Ylä-Outinen Laura, Jalkanen Aaro, Karppinen Jari E, Vieira-Potter Victoria Jeanne, Lipponen Arto, Karvinen Sira
Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland.
Montreal Heart Institute, Montréal, QC, Canada.
Front Neurosci. 2024 Jun 25;18:1399229. doi: 10.3389/fnins.2024.1399229. eCollection 2024.
Estrogen deficiency is associated with unfavorable changes in body composition and metabolic health. While physical activity ameliorates several of the negative effects, loss of ovarian function is associated with decreased physical activity levels. It has been proposed that the changes in brain neurochemical levels and /or impaired skeletal muscle function may underlie this phenomenon.
We studied the effect of estrogen deficiency induced via ovariectomy (OVX) in female Wistar rats ( = 64). Rats underwent either sham or OVX surgery and were allocated thereafter into four groups matched for body mass and maximal running capacity: sham/control, sham/max, OVX/control, and OVX/max, of which the max groups had maximal running test before euthanasia to induce acute response to exercise. Metabolism, spontaneous activity, and maximal running capacity were measured before (PRE) and after (POST) the surgeries. Three months following the surgery, rats were euthanized, and blood and tissue samples harvested. Proteins were analyzed from gastrocnemius muscle and retroperitoneal adipose tissue via Western blot. Brain neurochemical markers were measured from nucleus accumbens (NA) and hippocampus (HC) using ultra-high performance liquid chromatography.
OVX had lower basal energy expenditure and higher body mass and retroperitoneal adipose tissue mass compared with sham group ( ≤ 0.005). OVX reduced maximal running capacity by 17% ( = 0.005) with no changes in muscle mass or phosphorylated form of regulatory light chain (pRLC) in gastrocnemius muscle. OVX was associated with lower serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) level in the NA compared with sham ( = 0.007). In response to acute exercise, OVX was associated with low serotonin level in the HC and high level in the NA ( ≤ 0.024).
Our results highlight that OVX reduces maximal running capacity and affects the response of brain neurochemical levels to acute exercise in a brain region-specific manner. These results may offer mechanistic insight into why OVX reduces willingness to exercise.
雌激素缺乏与身体成分和代谢健康的不良变化有关。虽然体育活动可改善其中一些负面影响，但卵巢功能丧失与身体活动水平降低有关。有人提出，大脑神经化学水平的变化和/或骨骼肌功能受损可能是这一现象的基础。
我们研究了通过卵巢切除术（OVX）诱导雌性Wistar大鼠（n = 64）雌激素缺乏的影响。大鼠接受假手术或OVX手术，然后根据体重和最大跑步能力分为四组：假手术/对照组、假手术/最大组、OVX/对照组和OVX/最大组，其中最大组在安乐死前行最大跑步测试以诱导对运动的急性反应。在手术前（PRE）和手术后（POST）测量代谢、自发活动和最大跑步能力。手术后三个月，对大鼠实施安乐死，并采集血液和组织样本。通过蛋白质印迹法分析腓肠肌和腹膜后脂肪组织中的蛋白质。使用超高效液相色谱法测量伏隔核（NA）和海马体（HC）中的大脑神经化学标记物。
与假手术组相比，OVX组的基础能量消耗较低，体重和腹膜后脂肪组织质量较高（P≤0.005）。OVX使最大跑步能力降低了17%（P = 0.005），腓肠肌的肌肉质量或调节轻链的磷酸化形式（pRLC）没有变化。与假手术组相比，OVX组NA中的血清素代谢物5-羟吲哚乙酸（５-HIAA）水平较低（P = 0.007）。在急性运动反应中，OVX组与HC中血清素水平低和NA中血清素水平高有关（P≤0.024）。
我们的结果表明，OVX降低了最大跑步能力，并以脑区特异性方式影响大脑神经化学水平对急性运动的反应。这些结果可能为OVX降低运动意愿的原因提供机制性见解。
