European sea bass gill pathology after exposure to cadmium and terbuthylazine: expert versus fractal analysis

Abstract

The objective of this study was to compare expert versus fractal analysis as new methods to evaluate branchial lamellar pathology in European sea bass Dicentrarchus labrax (Linnaeus, 1758) experimentally exposed to cadmium and to terbuthylazine. In particular, guided expert quantitative and fractal analysis were performed on selected images from semithin sections to test possible differences according to exposure class (unexposed, cadmium exposed, or terbuthylazine exposed) and the discrimination power of the two methods. With respect to guided expert quantitative analysis, the following elementary pathological features were assessed according to pre-determined cover classes: 'epithelial lifting', 'epithelial shrinkage', 'epithelial swelling', 'pillar cells coarctation', 'pillar cells detachment', 'channels fusion', 'chloride cells swelling' and 'chloride cells invasion'. Considering fractal analysis, DB (box dimension), DM (mass dimension), Dx (mean fractal dimension) as fractal dimensions and lacunarity from DM and Dx scan types were calculated both from the outlined and skeletonized (one pixel wide lines) images. Despite significant differences among experimental classes, only expert analysis provided good discrimination with correct classification of 91.7 % of the original cases, and of 87.5 % of the cross-validated cases, with a sensitivity of 95.45 % and 91.3 %, respectively, and a specificity of 75 % in both cases. Guided expert quantitative analysis appears to be a reliable method to objectively characterize fish gill pathology and may represent a powerful tool in environmental biomonitoring to ensure proper standardization and reproducibility. Though fractal analysis did not equal the discrimination power of the expert method, it certainly warrants further study to evaluate local variations in complexity or possible multiple scaling rules.

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

“…Apart from interfering with the integrity of the actin cytoskeleton, cadmium also alters the function of cadherin‐based cell‐cell adhesion (Choong, Liu, Xiao, & Templeton, ; Prozialeck & Edwards, ) and has been shown to disrupt vinculin‐ and focal adhesion kinase‐rich focal contacts through a Ca 2+ /calmodulin‐dependent protein kinase II (CaMK‐II) pathway (Choong et al, ). Cell coarctation and curling in branchial cells of Cd‐dosed European sea bass have been reported previously as a consequence of physical disruption of cell‐to‐cell and cell‐ to‐matrix adhesions (Manera et al, ; Manera, Sayyaf Dezfuli, et al, ). Moreover, concentration‐related and time‐related responses in the number and the area of MAs have been reported by the authors in the same experimental model (Giari et al, ).…”

“…Further reading for a review of the different methods to compute fractal dimension, of the related errors, biases affecting its estimates and of the mutual comparison among the different ways to compute it, is available in Seuront (). Some practical applications of fractal dimension and lacunarity to the comparative assessment of piscine pathological tissue features are available in Manera, Dezfuli, Borreca, and Giari (), Manera et al (), and Manera, Giari, et al ().…”

“…From a historical perspective, the first exhaustive treatise on the biological significance of form and its variation is “On growth and form” by the mathematical biologist D'Arcy Wentworth Thompson (Thompson, ). Currently, morphometric analysis is widely used to objectively assess tissue lesions while applications have also been reported in fish pathology (Baish & Jain, ; Cruz‐Roa et al, ; Diamond, Anderson, Bartels, Montironi, & Hamilton, ; Eid & Landini, ; Gurcan et al, ; Manera & Borreca, ; Manera, Giari, DePasquale, & Dezfuli, ; Manera, Sayyaf Dezfuli, DePasquale, & Giari, ; Pantic et al, ; Stankovic et al, ).…”

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.…”

Perspectives on Complexity, Chaos and Thermodynamics in Environmental Pathology

“…The adoption of morphometric techniques allows approaching them quantitatively (with evident improvement in the statistical evaluation of results) and testing them for possible complexity changes, prone to alter the thermodynamic asset of organism [ 20 , 68 ]. Referring to fish as key indicator organisms for laboratory and field ecotoxicological studies, gills can be referred to as the most extensive interface with aquatic environment and, accordingly, suitable biomarkers for aquatic pollution [ 80 , 81 ]. Though gill assessment is currently used in environmental and ecotoxicological studies, to date there is a lack of standardized methods to objectively quantify gill alterations and, as a consequence, lesions are assessed only qualitatively or semi-quantitatively [ 82 , 83 ].…”