Acupuncture Attenuates Radiation-Induced Salivary Gland Injury and Modulates Cholinergic Signaling in a Rat Model of Xerostomia

Background Radiation-induced xerostomia (RIX) is a common and debilitating complication of radiotherapy for head and neck cancer. Although acupuncture has shown clinical benefits in relieving xerostomia, its underlying mechanisms remain unclear. This study investigated the protective effects of acupuncture on radiation-induced salivary gland injury and explored its potential mechanisms in a rat model. Methods A total of 36 male Sprague–Dawley rats were randomly assigned to a normal group ( n = 12), a radiation model group ( n = 12), and an acupuncture group ( n = 12). Rats in the model and acupuncture groups received a single 5-Gy irradiation to the salivary gland region. The acupuncture group subsequently received daily acupuncture at Lieque (LU7), Zhaohai (KI6), and Chengjiang (CV24) for 14 days. Salivary gland histopathology was evaluated by hematoxylin and eosin staining. Acetylcholinesterase (AChE) expression in salivary glands, serum AChE activity, and serum transforming growth factor-β1 (TGF-β1) levels were assessed by histochemistry, colorimetry, and enzyme-linked immunosorbent assay, respectively. Results Irradiation induced significant salivary gland injury, including nuclear pyknosis, acinar atrophy, and glandular structural disruption. Acupuncture markedly alleviated these pathological changes and promoted tissue recovery. Quantitative analysis showed that AChE expression was significantly reduced in the acupuncture group compared with both the normal and irradiated model groups ( p < .001), suggesting enhanced cholinergic signaling. Although serum TGF-β1 levels increased after irradiation, no significant difference was observed between the acupuncture and model groups. Conclusions Acupuncture alleviated radiation-induced salivary gland injury and reduced AChE expression in irradiated rats. These findings suggest that enhanced cholinergic signaling may contribute to the therapeutic effects of acupuncture on RIX.