Key Laboratory of Application of Ecology and Environmental Protection in Plateau Wetland of Sichuan, Xichang University, Xichang, 415000, Sichuan Province, China.
Key Laboratory of Application of Ecology and Environmental Protection in Plateau Wetland of Sichuan, Xichang University, Xichang, 415000, Sichuan Province, China.
Ecotoxicol Environ Saf. 2020 Jan 30;188:109889. doi: 10.1016/j.ecoenv.2019.109889. Epub 2019 Nov 5.
It is known that abamectin (ABM) inflicts oxidative damage on aquatic animals; however, knowledge about the immune response under pesticide-induced oxidative stress is incomplete. In the present study, several cellular and humoral immune parameters, including total haemocyte counts (THC), lysosomal membrane stability (LMS), activities of acid phosphatase (ACP), alkaline phosphatase (AKP) and lysozyme (LZM) were investigated to reveal the effects of ABM exposure on the immune defence mechanisms of the important freshwater crab, Erocheir sinensis. According to the results, a significant increase of THC was found in low concentration groups (0.03 and 0.06 mg/L), while dramatic decreases occurred in high concentration groups (0.12 and 0.24 mg/L) after 96 h of exposure. We also detected significant increases of reactive oxygen species (ROS) in haemocytes at 0.12 and 0.24 mg/L, and there was a dose- and time-dependent decrease of lysosomal membrane stability. These results suggest that the excessive generation of ROS induced by ABM may be leading the massive collapse of lysosomal membrane, which in turn may be causing the sharp drop of haemocyte counts in E. sinensis. The increase of hydrolytic enzymes ACP and AKP at low concentrations and the decrease at high concentrations also indicate an immune response associated with haemocytes status under stress. However, activities of LZM decreased significantly. After injection of Aeromonas hydrophil, mortalities increased under exposure to ABM and were positively related to ABM concentration. These results confirm that ABM exposure has the ability to impair immune defence and result in the host's susceptibility to pathogens.
已知阿维菌素（ABM）会对水生动物造成氧化损伤；然而，关于农药诱导的氧化应激下免疫反应的知识并不完整。在本研究中，研究了几种细胞和体液免疫参数，包括总血细胞计数（THC）、溶酶体膜稳定性（LMS）、酸性磷酸酶（ACP）、碱性磷酸酶（AKP）和溶菌酶（LZM）的活性，以揭示 ABM 暴露对重要淡水蟹中华绒螯蟹免疫防御机制的影响。结果表明，低浓度组（0.03 和 0.06mg/L）暴露 96 小时后 THC 显著增加，而高浓度组（0.12 和 0.24mg/L）则急剧下降。我们还检测到在 0.12 和 0.24mg/L 时血细胞中活性氧（ROS）的显著增加，并且溶酶体膜稳定性呈剂量和时间依赖性下降。这些结果表明，ABM 诱导的 ROS 过度产生可能导致溶酶体膜大量崩溃，从而导致中华绒螯蟹血细胞计数急剧下降。低浓度下水解酶 ACP 和 AKP 的增加和高浓度下的减少也表明在应激下与血细胞状态相关的免疫反应。然而，LZM 的活性显著下降。在注射嗜水气单胞菌后，暴露于 ABM 下的死亡率增加，并且与 ABM 浓度呈正相关。这些结果证实 ABM 暴露具有损害免疫防御并导致宿主易感染病原体的能力。
