Efficacy of Acupuncture and Identification of Tear Protein Expression Changes Using iTRAQ Quantitative Proteomics in Rabbits

Abstract

Purpose: To evaluate the effect of acupuncture on rabbit tear secretion and compare the difference in tear protein expression caused by acupuncture.

Materials and Methods: Ten male New Zealand White rabbits were enrolled in this study. The following acupoints around the left eye, Extra 1 (Taiyang), BL 2 (Zanzhu) and SJ 23 (Sizhukong), were selected for acupuncture therapy. Each rabbit received 10 acupuncture sessions of 30 min, three times per week. A quantity of 50 μl rabbit tear was collected at the pre- and post-acupuncture stage in every subject, respectively. Total protein content analysis, one-dimensional gel electrophoresis and quantitative proteomics analysis (iTRAQ) were performed and the results were compared.

Results: Generally, the tear protein expression after acupuncture was different from that before acupuncture though to some extent they were similar. The time spent collecting rabbit tear after acupuncture was shorter than that before acupuncture. The total protein content in rabbit tear pre- and post-acupuncture was 7.12 μg/μl versus 11.28 μg/μl, respectively. One-dimensional gel electrophoresis showed that tear proteins collected before acupuncture were substantially different than post-acupuncture proteins. In total, twenty-eight tear proteins were identified by iTRAQ. Associated with acupuncture were six up-regulated proteins (tear lipocalin, α-1-antiproteinase, histidine-rich glycoprotein, hemopexin, Vitamin D-binding protein, α-2-HS-glycoprotein) and five down-regulated proteins (Annexin A1, serum amyloid A-3 protein, Helicase-like transcription factor, 15 kDa protein A, protein S100-A9).

Conclusions: The rabbit tear protein expression difference caused by acupuncture indicates that acupuncture not only stimulates lacrimal gland secretion function but also induces the quantitative change of some proteins in rabbit tear, which may support a positive effect of acupuncture in the treatment of dry eye.

Keywords::

• Acupuncture
• Dry eye
• Tear protein
• One-dimensional gel electrophoresis
• Quantitative proteomics analysis (iTRAQ)

ACKNOWLEDGEMENTS

This work was supported by grants from National Natural Science Foundation of China (NO. 30873287) and Open Research Fund of State Key Laboratory of Medical Neurobiology, Fudan University. The authors thank the Department of Chemistry and the Institute of Biomedical Science, Fudan University, China, for technical support.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper. This work was supported by grants from National Natural Science Foundation of China (No. 30873287) and Open Research Fund of State Key Laboratory of Medical Neurobiology, Fudan University. The funding organization had no role in the design or conduct of this research.