Abstract:

This study aimed to investigate the effects and mechanisms of transient starvation on the metabolism and autophagy of porcine skeletal muscle satellite cells (SMSCs), to analyze the role of autophagy in skeletal muscle development, and to help design strategies for improving meat production traits in domestic pigs. Resuscitate the SMSCs cell lines isolated and preserved in the laboratory, and divide the cells into 5 groups based on the serum concentration: 20% serum group (control group), 15% serum group, 10% serum group, 5% serum group, and 0% serum group, to form varying degrees of hunger stress. When the cells fuse to 70%-80%, culture for 24 hours for detection, with 4 replicates in each group. Cell apoptosis, membrane potential, reactive oxygen species(ROS) levels were detected by flow cytometry; ATP levels were measured using a reagent kit, and the expression of autophagy marker proteins(LC3B-Ⅱ, p62) and pathway-related proteins(AMPK, mTOR) was detected by WB; transmission electron microscopy was used to detect changes in mitochondrial morphology and organelles in cells. The cell viability, level of p62 protein, and the p-mTOR/mTOR ratio decreased with the decrease of serum concentration; apoptosis rate, level of ROS, level of ATP, the level of LC3B-Ⅱ protein, the p-AMPK/AMPK ratio, the number of autophagy lysosomes and the abnormal rate of nucleus and mitochondria increased; Compared with the 20% serum concentration group, the 15% group showed a significant increase in membrane potential, while the 5% and 0% groups showed a highly significant decrease. This indicates that short-term serum starvation can induce autophagy induced by the AMPK/mTOR signaling pathway and accelerate cell metabolism, but at the cost of some toxic effects such as accelerating cell apoptosis and inhibiting cell proliferation.

Key words: porcine, autophagy, SMSCs, serum starvation, AMPK/mTOR pathway