title: Physiological responses and changes in gene expression in the large yellow croaker Larimichthys crocea following exposure to hypoxia.
abstract: Organisms at all levels of evolutionary complexity react to hypoxic stress. To clarify the effects of acute hypoxia on physiological and biochemical responses of Larimichthys crocea, we measured the activity levels of the antioxidant enzymes superoxide dismutase and catalase, hemoglobin concentration, functional indices of the liver (aspartate transaminase, alanine transaminase), heart (phosphocreatine kinase), and immune system (alkaline phosphatase), as well as mRNA expression levels of the immunity-related genes Hsp70 and HIF-1α at different time points of hypoxic. In addition, liver, gill, and kidney samples were histologically analyzed. We found that hemoglobin concentration and all enzyme activities increased during hypoxia, although these effects were transient and most indices returned to basal levels thereafter. The extent of the increase in the parameter values was inversely proportional to the dissolved oxygen content. Hsp70 and HIF-1α mRNA expression levels increased significantly in the blood, liver, gills, and kidneys following exposure to hypoxia, which may play an important role in protecting fish against oxidative damage. However, we found histological evidence of hypoxia-induced injuries to the gills, liver, and kidneys, which are involved in breathing, detoxification, and osmotic balance maintenance, respectively. Thus, despite the upregulation of defensive mechanisms, acute hypoxia still caused irreversible damage of organs. In conclusion, we observed that, in response to acute hypoxic stress, L. crocea enhances immune defensive function and antioxidant capacity. A better understanding of the regulation of the molecular anti-hypoxia mechanisms can help speeding up the selective breeding of hypoxia-tolerant L. crocea.
authors.affiliation: Key Laboratory of Applied Marine Biotechnology of Ministry of Education, College of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, China; Ningbo Academy of Oceanology and Fishery, Zhejiang 315012, China.
authors.forename: Qian-Feng
authors.initials: QF
authors.lastname: Wang
authors.affiliation: Ningbo Academy of Oceanology and Fishery, Zhejiang 315012, China.
authors.forename: Wei-Liang
authors.initials: WL
authors.lastname: Shen
authors.affiliation: Key Laboratory of Applied Marine Biotechnology of Ministry of Education, College of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, China.
authors.forename: Cong-Cong
authors.initials: CC
authors.lastname: Hou
authors.affiliation: Key Laboratory of Applied Marine Biotechnology of Ministry of Education, College of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, China; Ningbo Academy of Oceanology and Fishery, Zhejiang 315012, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Liu
authors.affiliation: Ningbo Academy of Oceanology and Fishery, Zhejiang 315012, China.
authors.forename: Xiong-Fei
authors.initials: XF
authors.lastname: Wu
authors.affiliation: Key Laboratory of Applied Marine Biotechnology of Ministry of Education, College of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, China. Electronic address: zhujunquan@nbu.edu.cn.
authors.forename: Jun-Quan
authors.initials: JQ
authors.lastname: Zhu
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001219:Aspartate Aminotransferases / Q000097:blood; D002374:Catalase / Q000378:metabolism*; D052279:Creatine Kinase, MB Form / Q000097:blood; D015870:Gene Expression; D005786:Gene Expression Regulation; D005880:Gills / Q000293:injuries* / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D000860:Hypoxia / Q000473:pathology*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000096:biosynthesis / Q000235:genetics; D007668:Kidney / Q000293:injuries* / Q000378:metabolism; D008099:Liver / Q000293:injuries* / Q000378:metabolism; D010473:Perciformes / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000097:blood; D013482:Superoxide Dismutase / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D018840:HSP70 Heat-Shock Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger; D002374:Catalase; D013482:Superoxide Dismutase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D052279:Creatine Kinase, MB Form; D000469:Alkaline Phosphatase
keywords: Antioxidant system; HIF-1α; Histology; Hsp70; Hypoxia; Larimichthys crocea