Zhang Yufan, Ye Chaoxia, Wang Anli, Zhu Xuan, Chen Changhong, Xian Jianan, Sun Zhenzhu
Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, Key Laboratory of Safe and Healthy Aquaculture in Guangdong Province, College of Life Science, South China Normal University, Guangzhou, 510631, People's Republic of China.
Ecotoxicology. 2015 Oct;24(7-8):1601-10. doi: 10.1007/s10646-015-1477-x. Epub 2015 May 13.
The residual contaminators such as ammonia and nitrite are widely considered as relevant sources of aquatic environmental pollutants, posing a great threat to shrimp survival. To study the toxicological effects of ammonia and nitrite exposure on the innate immune response in invertebrates, we investigated the oxidative stress and apoptosis in haemocytes of freshwater prawn (Macrobrachium rosenbergii) under isolated and combined exposure to ammonia and nitrite in order to provide useful information about adult prawn immune responses. M. rosenbergii (13.44 ± 2.75 g) were exposed to 0, 5, and 25 mg/L total ammonia-N (TAN) and 0, 5, and 20 mg/L nitrite-N for 24 h. All ammonia concentrations were combined with all nitrite concentrations, making a total of nine treatments studied. Following the exposure treatment, antioxidant enzyme activity, reactive oxygen species (ROS) generation, nitric oxide (NO) generation, and apoptotic cell ratio of haemocytes were measured using flow cytometry. Results indicated that ROS generation was sensitive to the combined effect of ammonia and nitrite, which subsequently affected the Cu-Zn SOD activity. In addition, CAT showed the highest activity at 5 mg/L TAN while GPx decreased at 5 mg/L TAN and returned towards baseline at 25 mg/L. NO generation synchronized with the apoptotic cell ratio in haemocytes, indicating that NO production was closely associated with programmed cell death. Both NO production and apoptotic ratios significantly decreased following 25 mg/L TAN, which may be due to the antagonistic regulation of NO and GPx. We hypothesized that the toxicological effect of nitrite exhibited less change in physiological changes compared to that of ammonia, because of the high tolerance to nitrite exposure in mature M. rosenbergii and/or the competitive effects of chloride ions. Taken together, these results showed that ammonia and nitrite caused a series of combined oxidative stress and apoptosis in M. rosenbergi, but further studies are of great need to explain the mechanisms.
诸如氨和亚硝酸盐等残留污染物被广泛认为是水生环境污染物的相关来源，对虾的生存构成巨大威胁。为了研究氨和亚硝酸盐暴露对无脊椎动物先天免疫反应的毒理学影响，我们调查了淡水虾（罗氏沼虾）血细胞在单独和联合暴露于氨和亚硝酸盐情况下的氧化应激和细胞凋亡情况，以便提供有关成年虾免疫反应的有用信息。将体重为（13.44±2.75克）的罗氏沼虾暴露于0、5和25毫克/升的总氨氮（TAN）以及0、5和20毫克/升的亚硝酸盐氮中24小时。所有氨浓度与所有亚硝酸盐浓度进行组合，共研究了九种处理。暴露处理后，使用流式细胞术测量血细胞的抗氧化酶活性、活性氧（ROS）生成、一氧化氮（NO）生成以及凋亡细胞比例。结果表明，ROS生成对氨和亚硝酸盐的联合作用敏感，随后影响了铜锌超氧化物歧化酶（Cu-Zn SOD）的活性。此外，过氧化氢酶（CAT）在5毫克/升TAN时活性最高，而谷胱甘肽过氧化物酶（GPx）在5毫克/升TAN时下降，并在25毫克/升时恢复至基线水平。NO生成与血细胞中的凋亡细胞比例同步，表明NO产生与程序性细胞死亡密切相关。在25毫克/升TAN处理后，NO产生和凋亡比例均显著下降，这可能是由于NO和GPx的拮抗调节作用。我们推测，与氨相比，亚硝酸盐的毒理学效应在生理变化方面表现出较小的变化，这是因为成熟的罗氏沼虾对亚硝酸盐暴露具有较高的耐受性和/或氯离子的竞争作用。综上所述，这些结果表明氨和亚硝酸盐在罗氏沼虾中引起了一系列联合氧化应激和细胞凋亡，但仍非常需要进一步研究来解释其机制。
