Division Livestock Sciences, Department of Sustainable Agricultural Systems, University of Natural Resources and Life Sciences Vienna, Vienna, Austria.
School of Agriculture and Food Sciences, The University of Queensland, Gatton, Qld, Australia.
J Anim Physiol Anim Nutr (Berl). 2021 May;105(3):549-557. doi: 10.1111/jpn.13504. Epub 2021 Feb 20.
Type 1 polysaccharide storage myopathy caused by genetic mutation in the glycogen synthase 1 gene is present in many breeds including the Noriker and Haflinger horses. In humans, EMG has already been used to document changes in the muscle activity patterns of patients affected by human glycogen storage disorders. Therefore, the aim of the present study was to describe gluteus muscle activity with surface electromyography (sEMG) in Haflinger and Noriker horses with known GYS1 mutation status during walk and trot. Thirty-two horses (11 Haflinger and 21 Noriker horses) with homozygous non-affected (GG), heterozygous affected (GA) and homozygous affected (AA) status of GYS1 mutation without overt clinical signs of any myopathy were selected for the current study. Using surface electromyography gluteus medius muscle activity at walk and at trot was measured, and muscle activity was described in relation to the maximum observed value at the same sensor and the same gait. In order to further describe the signals in detail comprising both frequencies and amplitudes, the crossings through the baseline and the 25, 50 and 75 percentile lines were determined. The result of the relative muscle activity did not show a consistent difference between affected and non-affected horses. Genetically affected (GA and AA) horses showed significantly less density of muscle activity for both gaits and horse breeds except for the crossings per second at the baseline and 75 percentile at walk in the Haflinger horses and 75 percentile at trot in the Noriker horses. The medians of all calculated density values were significantly lower in the GA Haflingers compared to the GG Haflingers (p = 0.012) and also in the AA Norikers compared to the GG Norikers (p = 0.011). Results indicate that the GYS1 mutation reduces the number of functional muscle fibres detected by sEMG measurements even in the absence of overt clinical signs.
1 型多糖贮积性肌病由糖原合酶 1 基因的基因突变引起，存在于许多品种中，包括挪威马和哈福林格马。在人类中，肌电图已被用于记录受人类糖原贮积病影响的患者肌肉活动模式的变化。因此，本研究的目的是描述已知 GYS1 突变状态的哈福林格马和挪威马在行走和小跑时的臀肌表面肌电图（sEMG）活动。选择 32 匹马（11 匹哈福林格马和 21 匹挪威马），具有纯合非受影响（GG）、杂合受影响（GA）和纯合受影响（AA）GYS1 突变状态，且没有明显的任何肌病的临床症状。使用表面肌电图测量臀中肌在行走和小跑时的活动，将肌肉活动与同一传感器和同一步态下观察到的最大活动值进行描述。为了更详细地描述信号，包括频率和幅度，确定了穿过基线和 25%、50%和 75%百分位线的交叉点。相对肌肉活动的结果并没有显示受影响和非受影响的马之间存在一致的差异。遗传受影响（GA 和 AA）的马在两种步态和两种马品种中表现出的肌肉活动密度明显较低，除了哈福林格马行走时的每秒交叉点和基线和 75%百分位线以及挪威马小跑时的 75%百分位线外。与 GG 哈福林格马相比，GA 哈福林格马的所有计算密度值中位数显著降低（p=0.012），与 GG 挪威马相比，AA 挪威马的所有计算密度值中位数也显著降低（p=0.011）。结果表明，即使在没有明显临床症状的情况下，GYS1 突变也会减少 sEMG 测量中检测到的功能性肌纤维数量。
