Climate change due to global warming can alter the salinity and pH in aquatic ecosystems. Low salinity (LS) and ocean acidification (OA) are stressors involved in osmotic regulation and can alter the antioxidant capacity of the body. In this study, we observed Na+/K+-ATPase (NKA) expression and activity in disk abalone gill tissue and changes in hemolymph osmolarity in relation to osmotic regulation over a short period (5 days). To confirm the degree of oxidative stress caused by changes in salinity and pH, changes in H2O2 levels, reactive oxygen species (ROS) levels, antioxidant enzyme (superoxide dismutase [SOD] and catalase [CAT]) expression, and caspase-7 expression were investigated at the molecular level. The degree of DNA damage was evaluated using the comet assay. mRNA expression, activity of gill NKA, and osmolarity of the hemolymph were significantly decreased in the LS group. Nonetheless, no noteworthy distinction was observed in mRNA expression or NKA activity between the control group and OA group. Hemolymph H2O2 levels and mRNA expression of SOD, CAT, and caspase-7 were significantly higher under the LS + OA condition than under single conditions of LS and OA. Further, caspase-7 mRNA expression and DNA damage increased with increasing exposure time. The group exposed to LS + OA showed the highest levels of caspase-7 expression and DNA damage. These results indicate that a combination of low salinity and pH induces more stress than a single condition does. Unmanageable ROS-mediated stress caused by environmental changes can lead to cell death and DNA damage.
Kim M. J., Kil G. S., Park Y. S. & Choi C. Y., 2023. Short-term exposure to combined condition of low salinity and pH affects ROS-mediated stress in disk abalone (Haliotis discus hannai). Ocean Science Journal 58: 21. doi: 10.1007/s12601-023-00115-0. Article.
