Schwindt Adam R, Truelove Nathan, Schreck Carl B, Fournie John W, Landers Dixon H, Kent Michael L
Department of Microbiology, Center for Fish Disease Research, 220 Nash Hall, Oregon State University, Corvallis, Oregon 97331-3804, USA.
Dis Aquat Organ. 2006 Jan 30;68(2):101-13. doi: 10.3354/dao068101.
Macrophage aggregates (MAs) occur in various organs of fishes, especially the kidney, liver and spleen, and contain melanin, ceroid/lipofuscin and hemosiderin pigments. They have been used as indicators of a number of natural and anthropogenic stressors. Macrophage aggregates occur in salmonids but are poorly organized, irregularly shaped, and are generally smaller than those in derived teleosts. These features complicate quantification, and thus these fishes have seldom been used in studies correlating MAs with environmental stressors. To alleviate these complications, we developed color filtering algorithms for use with the software package ImagePro Plus (Media Cybernetics) that select and quantify pigmented area (i.e. colors ranging from gold to brown to black) in tissue sections. Image analysis results compared well with subjective scoring when tested on brook trout Salvelinus fontinalis and rainbow trout Oncorhynchus mykiss captured from high-elevation lakes or hatcheries. Macrophage aggregate pigments correlated positively with age and negatively with condition factor. Within individual fish, pigmentation correlated positively among organs, suggesting that the kidney, liver or spleen are suitable indicator organs. In age-matched fishes, MA pigments were not different between hatcheries and lakes in the organs examined. Between lakes, differences in pigments were observed in the kidney and spleen, but were not explained by age, condition factor, sex or maturation state. Our results indicate that quantification of the area occupied by MA pigments is an efficient and accurate means of evaluating MAs in salmonid organs and that organ pigmentation correlates with age and condition factor, as seen in studies with more derived fishes.
巨噬细胞聚集体（MAs）存在于鱼类的各种器官中，尤其是肾脏、肝脏和脾脏，并且含有黑色素、类蜡质/脂褐素和含铁血黄素色素。它们已被用作多种自然和人为应激源的指标。巨噬细胞聚集体存在于鲑科鱼类中，但结构不佳，形状不规则，且通常比其他硬骨鱼中的聚集体小。这些特征使得量化变得复杂，因此这些鱼类很少被用于将巨噬细胞聚集体与环境应激源相关联的研究中。为了缓解这些复杂问题，我们开发了用于ImagePro Plus软件包（Media Cybernetics公司）的颜色过滤算法，该算法可选择并量化组织切片中的色素沉着区域（即从金色到棕色再到黑色的颜色范围）。在从高海拔湖泊或孵化场捕获的溪鳟Salvelinus fontinalis和虹鳟Oncorhynchus mykiss上进行测试时，图像分析结果与主观评分结果吻合良好。巨噬细胞聚集体色素与年龄呈正相关，与状况因子呈负相关。在个体鱼体内，各器官之间的色素沉着呈正相关，这表明肾脏、肝脏或脾脏是合适的指示器官。在年龄匹配的鱼类中，在所检查的器官中，孵化场和湖泊中的巨噬细胞聚集体色素没有差异。在不同湖泊之间，肾脏和脾脏中观察到色素差异，但年龄、状况因子、性别或成熟状态无法解释这些差异。我们的结果表明，量化巨噬细胞聚集体色素所占面积是评估鲑科鱼类器官中巨噬细胞聚集体的一种有效且准确的方法，并且器官色素沉着与年龄和状况因子相关，这与在其他硬骨鱼的研究中所见一致。
