Acupuncture Pretreatment Reduces Skeletal Muscle Inflammatory Response in EIMD Rats by Activating cGAS-STING-NF-κB Signaling Pathway.

Acupuncture pretreatment (AP) has a good skeletal muscle protective effect. The present study investigated whether acupuncture pretreatment could improve ultrastructural changes and skeletal muscle inflammation in exercising skeletal muscle injury. Eighty-eight male SD rats were randomly divided into a blank group (C), an exercise group (E), and an acupuncture pretreatment group (AP). Among them, the E and AP groups were divided into five subgroups of 0h, 12h, 24h, 48h, and 72h according to the extraction time after exercise, with 11 groups and eight rats in each group. The study involved simulating skeletal muscle injury caused by intermittent downhill running centrifugal exercise. The researchers used various methods to observe changes in mitochondrial structure and cGAS-STING-NF-κB p65 protein content of classical inflammatory response signaling pathway. These methods included transmission electron microscopy to observe skeletal muscle, Western Blot to detect changes in protein content, and reverse transcription polymerase chain reaction (RT-qPCR method) to detect cytoplasmic mtDNA gene fragment ND1, D-LOOP and cGAS-STING- NF-κB p65 protein RNA. The aim was to investigate the changes in NF-κB p65 protein RNA. Changes in NF-κB p65 protein RNA content and mtDNA gene fragment ND1 and D-LOOP content; changes in serum IL-8 and IFN-β content were detected by enzyme-linked immunosorbent assay (ELISA); WB, RT-qPCR, ELISA assays aimed to study the skeletal muscle injury and mitochondrial structural damage in group E relationship skeletal muscle tissue level, cytoplasmic mtDNA fragment gene ND1, and D-LOOP content in skeletal muscle tissue of group E. In comparison to group C, the levels of cGAS-STING-NF-κB p65 protein expression and mRNA, and the serum levels of IL-8 and IFN-β were significantly higher in group E . However, the acupuncture pretreatment group (AP) reduced the extent of damage to skeletal muscle mitochondria and the levels of cytoplasmic mtDNA fragment genes ND1 and D-LOOP. Also, the high expression of cGAS-STING-NF-κB p65 protein, mRNA, and the levels of IL-8 and IFN-β were inhibited in the AP group. The results indicated that AP ameliorated exercise-induced skeletal muscle injury and reduced skeletal muscle inflammation produced after centrifugal exercise. This was achieved by inhibiting the overexpression of the cGAS-STING-NF-κB signaling pathway.