Present Address: Croce Rossa Italiana, Comitato Nazionale, Via Ramazzini 37, Roma, Italy.
Laboratorio di Medicina Sportiva del Cavallo "Franco Tradati", Università degli Studi di Milano, Lodi, Italy.
BMC Vet Res. 2021 Mar 16;17(1):121. doi: 10.1186/s12917-021-02818-9.
Glycogen in skeletal muscle is a major source of energy during exercise and an important determinant of endurance capacity, so that its measurement may provide a meaningful marker of athletes' preparation and a possible predictor of performance, both in humans and in equines. Gold standard of glycogen concentration measurement is the histochemical and biochemical analysis of biopsy-derived muscle tissue, an invasive and potentially injuring procedure. Recently, high-frequency ultrasound (US) technology is being exploited in human sports medicine to estimate muscle glycogen content. Therefore, aim of the present study is to evaluate the feasibility of US assessment of muscle glycogen in equines.
US images of gluteus medius (GL) and semitendinosus (ST) muscles were obtained on eight healthy horses (3-10 years) before and after a steady-state exercise on treadmill (velocity: 4.0-12.5 m/s; duration: 2-20 min; heart rate: 137-218 b/min). Average image greyscale intensity was significantly different between GL and ST, both before and after exercise (p < 0.001). Comparing baseline and post-exercise US images, significant increase in greyscale intensity has been observed in ST (p < 0.001), but not in GL (p = 0.129). The volume of the exercise was significantly correlated with exercise-dependent change in image intensity (R = 0.891), consistent with a reduction of glycogen muscle stores resulting from aerobic activity.
US technique evidences also in horses muscle changes possibly associated to glycogen utilisation during exercise. Present results on a small sample need to be further confirmed and provide preliminary data warranting future validation by direct glycogen measurement through biopsy technique.
骨骼肌中的糖原是运动过程中的主要能量来源，也是耐力能力的重要决定因素，因此其测量可能为运动员的准备情况提供有意义的标志物，并可能预测人类和马的运动表现。糖原浓度测量的金标准是对活检获得的肌肉组织进行组织化学和生化分析，这是一种侵入性的、潜在的损伤性的程序。最近，高频超声（US）技术在人类运动医学中被用于估计肌肉糖原含量。因此，本研究旨在评估 US 评估马肌肉糖原的可行性。
在 8 匹健康马（3-10 岁）进行跑步机稳态运动（速度：4.0-12.5 m/s；持续时间：2-20 分钟；心率：137-218 b/min）前后，获得了臀中肌（GL）和半腱肌（ST）肌肉的 US 图像。运动前后，GL 和 ST 的平均图像灰度强度均存在显著差异（p < 0.001）。比较基线和运动后的 US 图像，发现 ST 的灰度强度显著增加（p < 0.001），但 GL 没有（p = 0.129）。运动体积与运动依赖的图像强度变化显著相关（R = 0.891），这与有氧活动导致的糖原肌肉储存减少一致。
US 技术也在马的肌肉中显示出可能与运动过程中糖原利用相关的变化。需要进一步确认小样本量的现有结果，并提供初步数据，以通过活检技术进行直接糖原测量进行未来验证。
