Acupoint Catgut Embedding Improves Lipid Metabolism in Exercise-Induced Fatigue Rats via the PPAR Signaling Pathway

SIMPLE SUMMARY: To improve the phenomenon of exercise-induced fatigue that often occurs during horse racing, we previously studied the improvement in exercise tolerance by acupoint catgut embedding preconditioning in an exercise-induced fatigue rat model. We found that acupoint catgut embedding pretreatment effectively improved animal exercise tolerance, but the mechanisms underlying these effects remain unclear. In this study, we explored the underlying mechanisms of this improvement by transcriptomic analysis. We showed that the PPAR signaling pathway was enriched through transcriptomic data analysis. Similarly, the mRNA expression levels of solute carrier family 27 member 2 (Slc27a2), fatty acid binding protein 1 (Fabp1), and apolipoprotein C3 (Apoc3) genes in the peroxisome proliferator-activated receptor (PPAR) pathway were decreased in the acupoint catgut group compared to the treadmill group. Further, to further explore the role of PPAR, we also detected the lipid metabolism index by using metabolomics. We found that acupoint embedding can correct the lipid metabolism index, i.e., free fatty acids (FFAs), arachidonic acid (AA), triglyceride (TG), etc., in the blood. Our study demonstrated that acupoint catgut embedding regulates the PPAR signaling pathway and further improves body fat metabolism. Our findings provide an important step to understanding how acupuncture catgut embedding improves exercise-induced fatigue (EF). ABSTRACT: To improve the phenomenon of exercise-induced fatigue that often occurs during horse racing, we previously studied the improvement in exercise tolerance by acupoint catgut embedding preconditioning in an exercise-induced fatigue rat model. We found that acupoint catgut embedding pretreatment effectively improved animal exercise tolerance. Here, by combining transcriptomics and metabolomics, we aimed to explore the underlying mechanisms of this improvement. We used blood biochemical detection combined with ELISA to detect triglyceride (TG), total cholesterol (TC), lactate dehydrogenase (LDH), high-density lipoprotein (HDL), alanine transaminase (ALT), aspartate aminotransferase (AST), and glucose (GLU), arachidonic acid (AA), and free fatty acid (FFA) content and found that acupoint embedding can correct FFA, AA, TG, LDH, and AST in the blood. We used RT-qPCR to measure the expression of genes in tissue from the quadriceps femoris muscle. We found that solute carrier family 27 member 2 (Slc27a2), fatty acid binding protein 1 (Fabp1), apolipoprotein C3 (Apoc3), and lipoprotein lipase (Lpl) genes in the peroxisome proliferator-activated receptor (PPAR) signaling pathway were important. The regulation of lipid metabolism through the PPAR signaling pathway was important for improving the exercise endurance of rats in our exercise-induced fatigue model. Therefore, we conclude that acupoint catgut embedding can not only promote body fat decomposition and reduce lactic acid accumulation but also promote the repair of tissue damage and liver damage caused by exercise fatigue. Acupoint catgut embedding regulates the PPAR signaling pathway by upregulating Lpl expression and downregulating Slc27a2, Fabp1, and Apoc3 expression to further improve body fat metabolism.