title: Immune toxicity of TiO₂ under hypoxia in the green-lipped mussel Perna viridis based on flow cytometric analysis of hemocyte parameters.
abstract: The combined effects of DO and TiO2 (mixed rutile/anatase phase, 7/3) on immune responses in Perna viridis were examined. Mussels were exposed to six combinations of oxygen levels (hypoxia: 1.5 mg O2l(-1), normoxia: 6.0 mg O2 l(-1)) and TiO2 concentrations (0, 2.5 mg l(-1) and 10 mg l(-1)) for 216 h. Mussels were sampled after 24h, 48h, 120 h and 216 h, and immune parameters of hemocytes, including mortality, phagocytosis, non-specific esterase, ROS production, lysosomal content and total hemocyte count were investigated using flow cytometric assay. Hemocyte mortality was higher under hypoxia than normoxia, and increased with TiO2 concentrations, but no interaction was found between DO and TiO2. Phagocytosis was reduced under hypoxia and decreased with TiO2 exposure, and the interactive effect between time and TiO2 was observed. The percentage of hemocytes showing non-specific esterase activity was lower under hypoxia, and decreased as TiO2 concentration increased with the significant interactive effect of DO and TiO2. ROS production and lysosomal content were lower under hypoxia and reduced as concentration of TiO2 increased, and interactive effect of DO and TiO2 on ROS was evident. THC was significantly affected by the interactive effect between TiO2 and DO, with higher values under normoxia in the presence of TiO2. The present study demonstrated that immune functions of P. viridis were influenced by both nano-TiO2 and hypoxia with some synergistic effects between the two stressors. This implies that DO has to be considered in the evaluation of the toxicity of nano-materials to bivalves.
authors.affiliation: College of Fisheries and Life Science, Shanghai Ocean University, 999 Huchenghuan Road, Shanghai 201306, China; Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China. Electronic address: youjiwang2@gmail.com.
authors.forename: Youji
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Fisheries and Life Science, Shanghai Ocean University, 999 Huchenghuan Road, Shanghai 201306, China; Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
authors.forename: Menghong
authors.initials: M
authors.lastname: Hu
authors.affiliation: Guangxi Institute of Fisheries, Nanning, Guangxi, 530021, China.
authors.forename: Qiongzhen
authors.initials: Q
authors.lastname: Li
authors.affiliation: College of Fisheries and Life Science, Shanghai Ocean University, 999 Huchenghuan Road, Shanghai 201306, China.
authors.forename: Jiale
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Environmental Science, Zhejiang University, Hangzhou 310058, China.
authors.forename: Daohui
authors.initials: D
authors.lastname: Lin
authors.affiliation: College of Fisheries and Life Science, Shanghai Ocean University, 999 Huchenghuan Road, Shanghai 201306, China. Electronic address: wqlv@shou.edu.cn.
authors.forename: Weiqun
authors.initials: W
authors.lastname: Lu
mesh_terms: D000818:Animals; D005434:Flow Cytometry; D006434:Hemocytes / Q000276:immunology; D000860:Hypoxia; D007107:Immune System / Q000187:drug effects* / Q000378:metabolism; D010100:Oxygen / Q000032:analysis; D049883:Perna / Q000276:immunology*; D010587:Phagocytosis / Q000187:drug effects; D014025:Titanium / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D014025:Titanium; D010100:Oxygen
keywords: Flow cytometry; Hemocyte; Hypoxia; Immune toxicity; Mussel; Nano-TiO(2)