To observe the effect of acupuncture on the AMPK/SIRT1/PGC- 1α signaling pathway in skeletal muscle of aging rats, and to explore the possible mechanism of acupuncture in delaying aging skeletal muscle atrophy in lumbar skeletal muscle.

Forty male SD rats were randomly divided into blank group, model group, acupuncture group and non-acupoint group. The blank group received daily subcutaneous injections of normal saline in the dorsal neck region. The other three groups received daily subcutaneous injections of D-galactose (D-gal) in the same region for 12 weeks to induce aging. Starting from week 9, acupuncture intervention was performed for 4 weeks. The acupuncture group took bilateral L3—L5 Jiaji points, and the non-acupoint group took bilateral non-meridian and non-acupoint points. Body weight and growth rates were measured, and muscle strength was evaluated using a grip strength test. Lumbar skeletal muscle atrophy was assessed using hematoxylin and eosin staining. Serum levels of superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-PX) were analyzed biochemically. Relative expression levels of AMPKα, SIRT1, PGC-1α, P21 and P53 mRNA were detected by real-time quantitative PCR.

Compared with the blank group, the body weight of the model group, the acupuncture group and the non-acupoint group was reduced (P<0.01, P<0.05, P<0.01), and the difference in terminal body weight growth rate was significant (P<0.001 for all). Before intervention, grip strength was significantly reduced in all experimental groups compared to the blank group (P<0.01 for all), with no significant differences among the experimental groups (P>0.05). After the intervention, the model group showed significantly lower grip strength compared to the blank group (P<0.001), accompanied by evident lumbar skeletal muscle atrophy, as reflected by reduced muscle fiber area and diameter (P<0.001, P<0.01). Additionally, serum SOD and GSH-PX activities decreased (P<0.001, P<0.001), while MDA increased significantly (P<0.01). The mRNA expression levels of AMPKα, SIRT1, and PGC-1α decreased significantly (P<0.001, P<0.001, P<0.01), while the relative mRNA expression levels of P21 and P53 were higher than those in the blank group (P<0.05, P<0.01). Compared with the model group, the acupuncture group demonstrated increased grip strength (P<0.001), improved skeletal muscle fiber area and diameter (P<0.01, P<0.05), enhanced serum SOD and GSH-PX activities (P<0.001, P<0.01), reduced serum MDA levels (P<0.05), and elevated AMPKα, SIRT1, and PGC-1α mRNA expression (P<0.001, P<0.01, P<0.05). Moreover, P21 and P53 mRNA expression levels were significantly reduced in the acupuncture group (P<0.05, P<0.01), while there was no significant difference in the non-acupoint group (P>0.05).

Acupuncture at Jiaji points alleviated the atrophy of lumbar skeletal muscles, improved muscle strength and inhibited oxidative stress in aging rats. These effects may be mediated through the AMPK/SIRT1/PGC-1α signaling pathway.