Pigmented macrophages and related aggregates in the spleen of european sea bass dosed with heavy metals: Ultrastructure and explorative morphometric analysis

Abstract

The ultrastructure and morphometrics of pigmented macrophages (PMs) were assessed in the spleen of European sea bass experimentally dosed with Cd and Hg. PMs occurred either as solitary cells or as variably structured aggregations, defined as macrophage aggregates (MAs). Light microscopy revealed a high degree of morphological heterogeneity amongst MAs of all experimental groups. At the ultrastructural level, MAs showed a heterogeneous pigment content that was not influenced by the treatment. Cytoplasm rarefaction/vacuolation and euchromatic nuclei, were observed in PMs of dosed fish. Undosed and Cd-dosed samples differ significantly with regard to the following morphometric features: the Minor axis of the best fitting ellipse, Aspect Ratio, and Roundness. In Cd-dosed fish, MAs showed reduced size and complexity. Lacunarity showed significant differences between undosed and both Cd and Hg-dosed samples. These results suggest that heavy metals, and especially Cd, may influence the dynamics of PM aggregation/disaggregation. Variability in splenic MAs was observed both by light and electron microscopy. However, only the morphometric techniques adequately and objectively described the phenomenon, allowing a quantitative/statistical comparison of morphology among experimental groups. These morphometric analyses could be usefully applied in toxicological and ecotoxicological, as well as morpho-functional studies.

The Iconic Atlantic Goliath Grouper (Epinephelus itajara): A Comprehensive Assessment of Health Indices in the Southeastern United States Population

“…Additional analyses on liver tissue slides were conducted at Florida State University (Tallahassee, Florida, USA) to evaluate pigmented macrophage aggregates (PMAs), sometimes referred to as melano-macrophage centers, which are aggregates of highly pigmented phagocytes (40,41). These were a prominent feature of liver tissue identified from preliminary histological analyses in this study.…”

Effects of water contamination with heavy metals on pigmented macrophages in spleen of Vardar chub (Squalius vardarensis Karaman) from three rivers in the North-Eastern region of North Macedonia

“…PMAs are part of the immune system of fish and are present in fish spleen under normal conditions, but parameters of PMAs (Vv, V and PMAs/mm 2 ) may undergo changes under different influences (12,13,14). These parameters are suggested as biomarkers of pollution and its influence on PMAs and on fish health in general (10,13). Our results showed that in the autumn, the moderate presence of metals in the river water in combination with high level of nutrients has caused the significant increase of the Vv(PMAs, spleen) and V(PMAs) in the spleen of Vardar chub from the Kriva River.…”

“…Different pollutants that occur in surface waters, including metals, have been associated with changes in the fish immune system and their general health (5,6,7,8). Spleen is one of the main organs in fish immune defense, and changes in spleen size and structure are considered indicative of negative impact of water pollution (7,9,10,11). Spleen, among other organs such as kidney, liver, gills, and others, is a site of aggregation of pigmented macrophages (PMAs).…”

Perfluorooctanoic Acid Exposure Assessment on Common Carp Liver through Image and Ultrastructural Investigation

“…Interestingly, fractal box counting applies also to real objects not strictly self-similar [77], not being the latter property mandatory for fractal analysis according to recognized authors [70,76,78]. Fractal analysis has proven useful to deal with complexity in bio-medical imaging and diagnosis [73][74][75] and has also been applied to fish histology [18,[79][80][81]. During the present survey, grayscale differential box counting was utilized to assess the complexity variation of the microscopic texture in liver of carp due to PFOA exposure.…”