Neuroprotective Mechanisms and Clinical Evidence for Acupuncture in Parkinson's Disease: A Systematic Review

Parkinson's disease (PD) is the second most common neurodegenerative disorder worldwide, and the mainstay of treatment is dopamine replacement therapy; however, its beneficial effects tend to wane over time as the disease progresses. Many patients seek complementary therapies to alleviate motor and nonmotor symptoms associated with PD, and the efficacy of acupuncture as a commonly used complementary and alternative therapy for PD remains controversial. In this review, we systematically examine randomized controlled trials and mechanistic studies on acupuncture for PD over the past 12 years. The findings indicate that acupuncture improves both motor and nonmotor symptoms. We also found that the mechanisms underlying the effects of acupuncture on PD may involve connectomics, modulation of dopamine and glutamate systems, regulation of the gut-brain axis, organelle homeostasis, and molecular and signaling pathway modulation. This review proposes a multitarget neuroprotection hypothesis to provide a theoretical basis for standardized acupuncture research.