Acupuncture alleviates form-deprivation myopia by promoting dopamine secretion and suppressing ferroptosis, potentially involving the PACAP-AC/cAMP pathway.

INTRODUCTION: Acupuncture has shown potential in the clinical treatment of myopia. The research aimed to elucidate the underlying mechanism of acupuncture in treating myopia. MATERIAL AND METHODS: Guinea pigs were randomly divided into five groups: Control, form-deprivation myopia (FDM), FDM + sham acupuncture, FDM + acupuncture (BL1 "Jingming" and BL2 "Cuanzhu"), and FDM + acupuncture + SQ22536 (an adenylyl cyclase (AC) inhibitor). Retinal, choroidal, and scleral morphological changes and retinal apoptosis were assessed by hematoxylin and eosin (HE) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Retinal dopamine, cyclic adenosine monophosphate (cAMP), Fe2+, reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione (GSH) levels were measured using kits. Immunofluorescence and western blot were used to assess tyrosine hydroxylase (TH). Western blot was used to analyze retinal AC, pituitary adenylate cyclase-activating polypeptide (PACAP), solute carrier family 7 member 11 (SLC7A11), glutathione peroxidase 4 (GPX4), and scleral collagen type I alpha 1 chain (COL1A1). RESULTS: Acupuncture significantly improved FDM-induced ocular biometric abnormalities, alleviated retinal, choroidal, and scleral alterations, and restored scleral COL1A1 expression. Moreover, acupuncture notably increased dopamine and TH levels in FDM guinea pigs. In addition, acupuncture partially restored the levels of cAMP, AC, and PACAP in FDM guinea pigs. Acupuncture markedly reduced Fe2+, ROS, and MDA levels, and increased GSH, SLC7A11, and GPX4 levels in FDM guinea pigs. These effects were reversed by SQ22536. CONCLUSIONS: Acupuncture stimulation at BL1 and BL2 alleviates myopia by promoting dopamine secretion and inhibiting ferroptosis, which may be associated with the PACAP-AC/cAMP signaling pathway.