Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, Shanghai 201306, PR China.
Key Laboratory of Conventional Freshwater Fish Breeding and Health Culture Technology Germplasm Resources, Ministry of Agriculture, Suzhou Shenhang Eco-technology Development Limited Company, Suzhou 215221, China.
Fish Shellfish Immunol. 2017 Nov;70:121-128. doi: 10.1016/j.fsi.2017.08.039. Epub 2017 Aug 31.
Aeromonas hydrophila is the causative agent of bacterial septicemia that is frequently observed in grass carp, Ctenopharyngodon idellus. In this study, we evaluated the biological parameters and immune enzymes in the liver of grass carp following A. hydrophila infection and quantified the alterations in liver histology using a semi-quantitative system. For the biological parameters, we found that the liver somatic index (LSI) was more sensitive than Fulton's condition factor (CF) and was significantly decreased at three days post-injection (DPI). At the immune enzyme level, the level of peroxidase (POD) in the liver significantly increased at 1 and 3 DPI. The activity of alkaline phosphatase (ALP) significantly increased at 3 DPI. Similarly, acid phosphatase (ACP) activity significantly increased at 1, 3, and 5 DPI. Histologically, the results indicated that the liver index at 3, 5, and 7 DPI was significantly higher than that of control groups. The regressive alterations as the highly variable reactions patterns and its index at 5 DPI was significantly higher than that of 1, 21 DPI, and the control groups. Based on our results, we suggest that grass carp resist A. hydrophila infection via an innate immune mechanism in the liver. The findings of this study will help elucidate the underlying mechanisms of resistance to A. hydrophila infection.
嗜水气单胞菌是草鱼细菌性败血症的病原体。本研究评估了草鱼感染嗜水气单胞菌后肝脏的生物学参数和免疫酶，并采用半定量系统量化了肝组织学的变化。对于生物学参数，我们发现肝体指数（LSI）比富尔顿条件系数（CF）更敏感，在注射后 3 天（DPI）时显著降低。在免疫酶水平上，肝脏过氧化物酶（POD）的水平在 1 和 3 DPI 时显著增加。碱性磷酸酶（ALP）的活性在 3 DPI 时显著增加。同样，酸性磷酸酶（ACP）的活性在 1、3 和 5 DPI 时显著增加。组织学结果表明，3、5 和 7 DPI 的肝指数明显高于对照组。在 5 DPI 时的退行性变化及其指数明显高于 1、21 DPI 和对照组。根据我们的结果，我们认为草鱼通过肝脏的先天免疫机制来抵抗嗜水气单胞菌感染。本研究的结果将有助于阐明草鱼抵抗嗜水气单胞菌感染的潜在机制。
