Development and validation of an activated immune model with zebrafish eleutheroembryo based on caudal fin acupuncture

Environmental pollutants are ubiquitous in global aquatic ecosystems and may cause immunotoxicity in aquatic organisms. However, disadvantages remain in the existing in vivo immunotoxicological methods, which make it difficult to meet the increasing demands for screening and for discriminating the immunotoxicity of environmental pollutants. In this study, the immune response in zebrafish eleutheroembryo was activated by acupuncture of the caudal fin at 72 hours post fertilization (hpf), and this immune model was further validated with a well-defined immunosuppressor, beclomethasone dipropionate (BDP). It was shown that acupuncture resulted in no increase in mortality in zebrafish eleutheroembryos. The transcription and protein levels of most immune genes were significantly increased after acupuncture, which indicated that acupuncture can effectively activate the immune response in zebrafish eleutheroembryos. Following exposure to BDP (0.01-1 μmol/L), the suppressive effects on the immune system were more significant in zebrafish that received acupuncture than in zebrafish that did not receive acupuncture. Considering these advantages, including its sensitivity, safety, and simple operation, over existing methods, the established immune model of zebrafish is promising for assessing the immunotoxicity of environmental pollutants.