Objective: To study the effects of vibration on the expression of mitochondrial fusion and fission genes and ultrastructure of skeletal muscle in rabbits. Methods: Thirty-two 3.5-month-old New Zealand rabbits were randomly divided into low-intensity group, medium-intensity group, high-intensity group and control group, with 8 rabbits in each group. The rabbits in the experimental group were subjected to hind limb vibration load test for 45 days. The vibration intensity of the high intensity group was 12.26 m/s(2), the medium intensity group was 6.13 m/s(2), and the low intensity group was 3.02 m/s(2) according to the effective value of weighted acceleration[a(hw (4))] for 4 hours of equal energy frequency. The control group was exposed to noise only in the same experimental environment as the medium-intensity group. The noise levels of each group were measured during the vibration load experiment. After the test, the mRNA expression of mitochondrial fusion gene (Mfn1/Mfn2) and fission gene (Fis1, Drp1) by RT-PCR in the skeletal muscles were measured and the ultrastructure of the skeletal muscles were observed in high intensity group. Results: The mRNA expression of mitochondrial in the skeletal muscle tissues of control group, low intensity group, medium intensity group and high intensity group were Mfn1: 3.25±1.36, 3.85±1.90, 4.53±2.31 and 11.63±7.68; Mfn2: 0.68±0.25, 1.02±0.40, 0.94±0.33 and 1.40±0.45; Fis1: 1.05±0.62, 1.15±0.59, 1.53±1.06 and 2.46±1.51 and Drp1: 3.72±1.76, 2.91±1.63, 3.27±2.01 and 4.21±2.46, respectively. Compared with the control group, the expressions of Mfn1 mRNA, Mfn2 mRNA and Fis1 mRNA in the high-intensity group increased significantly (P<0.05) , and the expressions of Mfn2 mRNA in the medium-intensity group and the low-intensity group increased significantly (P<0.05) . Compared with the control group, the ultrastructure of skeletal muscle of high intensity group showed mitochondrial focal accumulation, cristae membrane damage, vacuole-like changes; Z-line irregularity of muscle fibers, and deficiency of sarcomere. Conclusion: Vibration must be lead to the abnormal mitochondrial morphology and structure and the disorder of energy metabolism due to the expression imbalance of mitochondrial fusion and fission genes in skeletal muscles of rabbits, which may be an important target of vibration-induced skeletal muscle injury.
目的： 探讨振动对骨骼肌线粒体融合基因与分裂基因表达及对骨骼肌超微结构的影响，为振动性骨骼肌损伤发生机制的研究提供基础资料。 方法： 于2019年6月，选取3.5月龄的新西兰家兔32只，按照4小时等能量频率计权加速度有效值[a(hw(4))]随机分组分为低强度组（3.02 m/s(2)）、中强度组（6.13 m/s(2)）、高强度组（12.26 m/s(2)）和对照组（与中强度组相同的实验环境，只接触噪声不接触振动），每组8只。对实验组家兔进行45 d的后肢振动负荷实验，实验结束后取其后肢骨骼肌，用荧光实时定量PCR（RT-PCR）进行线粒体融合基因（Mfn1/Mfn2）mRNA与分裂基因（Fis1、Drp1） mRNA表达的测定，并对高强度组家兔进行骨骼肌超微结构观察。 结果： 对照组、低强度组、中强度组、高强度组骨骼肌组织Mfn1 mRNA表达量为：3.25±1.36、3.85±1.90、4.53±2.31、11.63±7.68；Mfn2 mRNA表达量分别为：0.68±0.25、1.02±0.40、0.94±0.33、1.40±0.45；Fis1 mRNA表达量分别为：1.05±0.62、1.15±0.59、1.53±1.06、2.46±1.51；Drp1 mRNA表达量分别为：3.72±1.76、2.91±1.63、3.27±2.01、4.21±2.46。与对照组比较，高强度组家兔骨骼肌组织Mfn1 mRNA、Mfn2 mRNA、Fis1 mRNA的表达均明显增强；中强度组、低强度组的Mfn2 mRNA的表达明显增强，差异均有统计学意义（P<0.05）。超微结构观察显示，高强度组家兔骨骼肌出现线粒体灶性聚集、嵴膜损伤、空泡样改变，肌纤维Z线不齐、肌小节缺失等改变。 结论： 振动可造成家兔骨骼肌线粒体融合与分裂基因的表达失衡，并可能导致出现线粒体形态结构的异常以及能量代谢的紊乱，可能成为振动所致骨骼肌损伤的重要靶点。.
Keywords: Mitochondrial fusion and fission genes; Rabbit; Skeletal muscle; Ultrastructure; Vibration.