Laboratory of Ecological Immunology of Aquatic Organisms, A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS, Nakhimov Ave, 2, Sevastopol 299000, Russia.
Laboratory of Aquatic Ecotoxicology, A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS, Nakhimov Ave, 2, Sevastopol 299000, Russia.
Comp Biochem Physiol A Mol Integr Physiol. 2024 Oct;296:111682. doi: 10.1016/j.cbpa.2024.111682. Epub 2024 Jun 20.
The effect of water acidification in combination with normoxia or hypoxia on the antioxidant capacity and oxidative stress markers in gills and hemolymph of the Mediterranean mussel (Mytilus galloprovincialis), as well as on gill microstructure, has been evaluated through an in vivo experiment. Mussels were exposed to a low pH (7.3) under normal dissolved oxygen (DO) conditions (8 mg/L), and hypoxia (2 mg/L) for 8 days, and samples were collected on days 1, 3, 6, and 8 to evaluate dynamic changes of physiological responses. Cytoplasmic concentrations of reactive oxygen species (ROS) and levels of DNA damage were measured in hemocytes, while the activity of catalase (CAT) and superoxide dismutase (SOD) and histopathological changes were assessed in gills. The results revealed that while water acidification did not significantly affect the activity of SOD and CAT in gills under normoxic and hypoxic conditions, there was a trend towards suppression of CAT activity at the end of the experimental period (day 8). Similarly, we did not observe increased formation of ROS in hemocytes or changes in the levels of DNA damage during the experimental period. These results strongly suggest that the oxidative stress response system in mussels is relatively stable to experimental conditions of acidification and hypoxia. Experimental acidification under normoxia and hypoxia caused changes to the structure of the gills, leading to various histopathological alterations, including dilation, hemocyte infiltration into the hemal sinuses, intercellular edema, vacuolization of epithelial cells in gill filaments, lipofuscin accumulation, changes in the shape and adjacent gill filaments, hyperplasia, exfoliation of the epithelial layer, necrosis, swelling, and destruction of chitinous layers (chitinous rods). Most of these alterations were reversible, non-specific changes that represent a general inflammatory response and changes in the morphology of the gill filaments. The dynamics of histopathological alterations suggests an active adaptive response of gills to environmental stresses. Taken together, our data indicate that Mediterranean mussels have a relative tolerance to water acidification and hypoxia at tissue and cellular levels.
通过体内实验评估了酸化水与常氧或低氧结合对地中海贻贝（Mytilus galloprovincialis）鳃和血淋巴抗氧化能力和氧化应激标志物的影响，以及对鳃微观结构的影响。贻贝在低 pH 值（7.3）下暴露于正常溶解氧（DO）条件（8 mg/L）和低氧（2 mg/L）下 8 天，并在第 1、3、6 和 8 天收集样本以评估生理反应的动态变化。在血淋巴细胞中测量活性氧（ROS）的细胞质浓度和 DNA 损伤水平，而在鳃中评估过氧化氢酶（CAT）和超氧化物歧化酶（SOD）的活性和组织病理学变化。结果表明，尽管酸化水在常氧和低氧条件下对 SOD 和 CAT 在鳃中的活性没有显著影响，但在实验结束时（第 8 天）CAT 活性有抑制的趋势。同样，在实验期间，我们没有观察到血淋巴细胞中 ROS 的形成增加或 DNA 损伤水平的变化。这些结果强烈表明，贻贝的氧化应激反应系统对酸化和低氧的实验条件相对稳定。常氧和低氧下的实验酸化导致鳃结构发生变化，引起各种组织病理学改变，包括扩张、血窦内的血细胞浸润、细胞间水肿、鳃丝上皮细胞空泡化、脂褐素积累、鳃丝形状和相邻鳃丝改变、增生、上皮层剥落、坏死、肿胀和几丁质层（几丁质棒）破坏。这些改变大多是可逆的、非特异性的，代表一般的炎症反应和鳃丝形态的改变。组织病理学改变的动态表明鳃对环境应激具有积极的适应反应。综上所述，我们的数据表明地中海贻贝在组织和细胞水平上对水酸化和低氧具有相对的耐受性。
