Oxidative stress, DNA damage and antioxidant enzyme gene expression in the Pacific white shrimp, Litopenaeus vannamei when exposed to acute pH stress.
The ROS production, the percentage of dead and damaged haemocytes, the DNA Olive Tail Moment (OTM) value and the gene expression of manganese superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPx) and thioredoxin (TRx), were studied in the Pacific white shrimp, Litopenaeus vannamei, when exposed to acute pH stress. The increased ROS production in haemocytes and the increased OTM value in both the haemocytes and the hepatopancreas cells suggest that oxidative damage occurred in shrimp exposed to pH 5.6 and pH 9.3, with apoptosis, mainly being associated with excess Ca(2+)influx and changes in cell viability. Acid and alkaline pH-induced DNA damage was time dependent in the haemocytes and the hepatopancreas cells. The concentration of intracellular free calcium [Ca(2+)] (i) after different pH treatments increased significantly over time, reaching its highest concentration after 12 h, but decreasing gradually to normal levels after 24 h. The [Ca(2+)] (i) content in shrimp cells when exposed to pH 9.3 and pH 5.6 for 12 h had increased by 58%-81%, compared with exposure to pH 7.4 (control). In addition, the gene expression of cMnSOD, CAT, GPx and TRx in the hepatopancreas of L. vannamei was induced by acid and alkaline pH stress, although there were differences in the expression response with respect to the duration of induction and the different pH treatments (acid or alkaline). Our results show that acidic or alkaline-induced oxidative stress may cause DNA damage, and cooperatively activate expression of CAT, GPx and TRx mRNA. Calcium ions appear to be important in mediating shrimp responses to pH stress.
Wang
Wei-Na
WN
Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, College of Life Science, South China Normal University, Guangzhou 510631, PR China. wangwn@scnu.edu.cn
Zhou
Jun
J
Wang
Peng
P
Tian
Ting-Ting
TT
Zheng
Ying
Y
Liu
Yuan
Y
Mai
Wei-Jun
WJ
Wang
An-Li
AL
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D017209:Apoptosis / Q000235:genetics; D002118:Calcium / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002470:Cell Survival; D020552:Comet Assay; D004249:DNA Damage / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D005979:Glutathione Peroxidase / Q000378:metabolism; D006434:Hemocytes / Q000201:enzymology / Q000378:metabolism; D006458:Hemolymph / Q000201:enzymology / Q000378:metabolism; D043143:Hepatopancreas / Q000201:enzymology / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D018384:Oxidative Stress / Q000235:genetics*; D010140:Pacific Ocean; D033561:Penaeidae / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D016897:Respiratory Burst; D013312:Stress, Physiological; D013482:Superoxide Dismutase / Q000378:metabolism; D013879:Thioredoxins / Q000378:metabolism; D013997:Time Factors
D000975:Antioxidants; D017382:Reactive Oxygen Species; D013879:Thioredoxins; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D002118:Calcium