Uncommon hepatic macrophagic foamy‐cell nodules in Iberian barbel (Luciobarbus bocagei Steindachner, 1864) from the Vizela River (Portugal)

Abstract

The main intent of this work (after the by chance finding, in archived histological slides) is to characterize one previously non-described liver lesion of the Iberian barbel from the Vizela River (Portugal). This ran through a textile and dyeing industrial region. The lesion type was made of groups of foamy cells (presumptive macrophages), which appear either as a "smaller non-nodular form," without a connective tissue capsule and displaying an irregular profile, or as a "bigger nodular form," presenting a thin capsule and a circular profile. The nodular forms could appear multi-layered, resembling "cross-sectioned onions". The lesions number, dimension, and structural complexity were greater in bigger fish, appearing only after a history of poor water quality.In extreme cases, the lesions slightly protruded the liver surface. Special histological staining proved the connective tissue nature of the capsule (and its eventual septa), the presence of proteins, glycoproteins, lipofuscin, melanin, iron (putative hemosiderin), and copper, in a variable number of foamy cells within the lesions. At times, degenerating hepatocytes appeared at the border of the lesions. It is proposed that this lesion type incorporates both macrophages and degenerating hepatocytes, looking as one (unpublished) form of a macrophage aggregate. The term "foamy-cell nodules" was advanced for this abnormality. The lesion could have been induced by pollution, because: no parasites were ever associated with the lesion; there was coexistence of the lesion with a water quality status scored as "bad"; such lesion neither existed in fish sampled after mitigation and remediation measures nor in reference fish.

Seasonal Differences in Water Pollution and Liver Histopathology of Iberian Barbel (Luciobarbus bocagei) and Douro Nase (Pseudochondrostoma duriense) in an Agricultural Watershed

“…The lowest HSI in summer (0.84 for L. bocagei and 1.07 for P. duriense) is in agreement with the higher prevalence of histological changes, observed in both species and with the high concentrations of heavy metals measured in the water. Indeed, the work developed by Carrola et al [45], also with L. bocagei, evidenced a lower CF in polluted sites (0.89 and 0.84) than in control conditions (1.14). In contrast, the work developed by Gonino et al [15], in burned areas, and van Dyk et al [58], in polluted rivers, points in the opposite direction.…”

“…Coimbra et al [46] observed greater hepatic changes in fish caught in polluted sites, showing that the textile industry effluents interfere with the health of fish. Carrola [45] found uncommon hepatic macrophagic foamy-cell nodules in fish collected in years of poorer water quality classification. In addition, Raldúa et al [8] argue that Barbus graellsii collected downstream of industrial effluent discharges in the Vero river (Ebro basin, NE Spain) was affected by water pollution.…”

“…In the presence of environmentally stressful conditions, it has been documented that macrophages increase in size and frequency, suggesting they are reliable biomarkers for water quality in terms of deoxygenation and chemical pollution [44]. The presence of macrophage aggregates has also been documented in L. bocagei, at the Vizela River [45,46]. Coimbra et al [46] observed greater hepatic changes in fish caught in polluted sites, showing that the textile industry effluents interfere with the health of fish.…”