Comparisons of stereological and other approaches for quantifying macrophage aggregates in piscine spleens

Journal of Aquatic Animal Health
By: , and 

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Abstract

Macrophage aggregates (MA s) are focal accumulations of pigmented macrophages in the spleen and other tissues of fish. A central role of MA s is the clearance and destruction of degenerating cells and recycling of some cellular components. Macrophage aggregates also respond to chemical contaminants and infectious agents and may play a role in the adaptive immune response. Tissue damage or physiological stress can result in increased MA accumulation. As a result, MA s may be sensitive biomarkers of environmental stress in fish. Abundance of MA s in tissues has been reported in a variety of ways—most commonly as density, mean size, and relative area—but the utility of these estimates has not been compared. In this study, four different types of splenic MA abundance estimates (abundance score, density, relative area, and total volume) were compared in two fish populations (Striped Bass Morone saxatilis and White Perch M. americana ) with a wide range in ages. Stereological estimates of total volume indicated an increase in MA abundance with spleen volume, which generally corresponded to fish age, and with splenic infections (mycobacteria or trematode parasites). Abundance scores were generally limited in the ability to detect changes in MA abundance by these factors, whereas density estimates were greatly influenced by changes in spleen volume. In some instances, densities declined while the total volume of MA s and spleen volume increased. Experimentally induced acute stress resulted in a decrease in spleen volume and an increase in MA density, although the total volume of MA s remained unchanged. Relative area estimates accounted for the size and number of MA s but not for changes in organ volume. Total volume is an absolute measure of MA abundance irrespective of changes in organ volume or patterns of accumulation and may provide an improved means of quantifying MA s in the spleens of fish.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Comparisons of stereological and other approaches for quantifying macrophage aggregates in piscine spleens
Series title Journal of Aquatic Animal Health
DOI 10.1002/aah.10086
Volume 31
Issue 4
Year Published 2019
Language English
Publisher Wiley
Contributing office(s) Leetown Science Center
Description 21 p.
First page 328
Last page 348
Country United States
State Maryland
Other Geospatial Choptank River, Nanticoke River
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