Proteomic analysis of tears following acupuncture treatment for menopausal dry eye disease by two-dimensional nano-liquid chromatography coupled with tandem mass spectrometry

BACKGROUND: The purpose of this study was to investigate whether acupuncture is effective at treating dry eye disease among postmenopausal women and to identify the possible mechanisms. METHODS: Twenty-eight postmenopausal women with dry eye disease were randomly divided into two groups: an acupuncture plus artificial tears (AC + AT) group and an artificial tears (AT) only group. After baseline examination of clinical parameters and tear sample collection, each patient received the designated modality of topical therapy for 2 months. Post-treatment documentation of clinical parameters was recorded, and tear samples were collected. Tear samples from the AC + AT group were subjected to two-dimensional nano-liquid chromatography coupled with tandem mass spectrometry (2D nano-LC-MS/MS). Western blot analysis was also performed on tear samples from both groups. RESULTS: After treatment, the Ocular Surface Disease Index scores, symptom assessment scores, scores of sign assessment, and tear break-up time were significantly improved in both groups (P=0.000). Symptom assessment scores were significantly improved in the AC + AT group (P=0.000) compared with the AT group. 2D nano-LC-MS/MS identified 2,411 proteins, among which 142 were downregulated and 169 were upregulated. After combined AC + AT treatment, the abundance of secreted proteins was increased, whereas that of cytoplasmic proteins decreased (Pearson’s χ(2) test, P=0.000, P=0.000, respectively). Proteins involved in immunity and regulation were also more abundant (Pearson’s χ(2) test, P=0.040, P=0.016, respectively), while components and proliferation-related proteins were downregulated (Pearson’s χ(2) test, P=0.003, P=0.011, respectively). CONCLUSION: AC + AT treatment increased protein synthesis and secretion, and improved clinical symptoms. These results indicate that acupuncture may be a complimentary therapy for treating postmenopausal dry eye disease.