Wu Ping, Chen Lin, Cheng Jia, Pan Yaxiong, Zhu Xin, Chu Wuying, Zhang Jianshe
Department of Biological and Environmental Engineering, Changsha University, Changsha, China.
Key Laboratory of Protein Chemistry and Fish Developmental Biology of Education Ministry of China, College of Life Sciences, Hunan Normal University, Changsha, China.
J Fish Biol. 2022 Jul;101(1):168-178. doi: 10.1111/jfb.15081. Epub 2022 Jun 1.
In skeletal muscle, autophagy regulates the development and growth of muscle fibres and maintains the normal muscle metabolism. Under starvation and refeeding conditions, the effect of reactive oxygen species (ROS) levels on skeletal muscle autophagy is still unclear, although the excessive accumulation of ROS has been shown to increase autophagy in cells. The purpose of this study was to explore the effects of starvation and diet after starvation on the autophagy of adult Chinese perch muscle, and to determine the level of ROS in the muscle. We performed zero (Normal control), three and seven starvation treatments on adult Chinese perch, and returned to normal feeding for 3 days after starvation for 7 days. In the muscles of the adult Chinese perch muscle after 3 days of starvation, the autophagy marker protein LC3 and the number of autophagosomes remained basically the same as in the normal feeding situation. However, on starvation for 7 days, the mitochondrial autophagy was sensitive and the number of autophagosomes increased, but the antioxidant-related molecules (malondialdehyde, catalase, glutathione S-transferase, glutathione and anti-superoxide anion) decreased and the accumulation of ROS was obvious. In addition, the extended starvation time also increased the level of LC3 protein. However, by refeeding after starvation this nutritional stress resulted in a decrease in ROS levels and a partial restoration of antioxidant enzyme activity. Our data show that in the adult Chinese perch muscle, starvation could reduce the antioxidant activity through the accumulation of ROS, and that the number of autophagosomes continues to increase. Refeeding after starvation could effectively compensate for the level of ROS, and restore the mRNA abundance of antioxidant genes and the activity of antioxidant enzymes to reduce autophagy and improve feed efficiency. Further research should optimize starvation conditions to reduce autophagy in muscles and maintain normal muscle metabolism.
在骨骼肌中，自噬调节肌纤维的发育和生长，并维持正常的肌肉代谢。在饥饿和再投喂条件下，尽管活性氧（ROS）水平过高已被证明会增加细胞自噬，但ROS水平对骨骼肌自噬的影响仍不清楚。本研究的目的是探讨饥饿及饥饿后投喂对成年鲈鱼肌肉自噬的影响，并测定肌肉中ROS的水平。我们对成年鲈鱼进行了零天（正常对照）、三天和七天的饥饿处理，并在饥饿七天后恢复正常投喂三天。在饥饿三天后的成年鲈鱼肌肉中，自噬标记蛋白LC3和自噬体数量与正常投喂情况下基本相同。然而，饥饿七天时，线粒体自噬敏感，自噬体数量增加，但抗氧化相关分子（丙二醛、过氧化氢酶、谷胱甘肽S转移酶、谷胱甘肽和抗超氧阴离子）减少，ROS积累明显。此外，延长饥饿时间也会增加LC3蛋白水平。然而，饥饿后再投喂，这种营养应激导致ROS水平下降，抗氧化酶活性部分恢复。我们的数据表明，在成年鲈鱼肌肉中，饥饿会通过ROS积累降低抗氧化活性，且自噬体数量持续增加。饥饿后再投喂可有效补偿ROS水平，恢复抗氧化基因的mRNA丰度和抗氧化酶活性，以减少自噬并提高饲料效率。进一步的研究应优化饥饿条件，以减少肌肉中的自噬并维持正常的肌肉代谢。
