Effects of iron on rainbow trout gill cells in primary culture

Establishment and validation of a 2D primary gill cell culture of the sevenband grouper (Hyporthodus septemfasciatus)

A 2D primary gill cell culture system of the sevenband grouper (Hyporthodus septemfasciatus) was established to validate the pathogenesis of nervous necrosis virus (NNV) as observed in previous studies. This system, developed using the double-seeded insert (DSI) technique, yielded confluent cell layers. Upon challenge with NNV in a setup containing both autoclaved salt water and L15 media in the apical compartment, viral replication akin to that anticipated based on previous studies was observed. Consequently, we advocate for the utilization of primary gill cell culture as a viable alternative to conventional methodologies for investigating host pathogen interactions.

Profiling the Physiological Roles in Fish Primary Cell Culture

Fish primary cell culture has emerged as a valuable tool for investigating the physiological roles and responses of various cell types found in fish species. This review aims to provide an overview of the advancements and applications of fish primary cell culture techniques, focusing on the profiling of physiological roles exhibited by fish cells in vitro. Fish primary cell culture involves the isolation and cultivation of cells directly derived from fish tissues, maintaining their functional characteristics and enabling researchers to study their behavior and responses under controlled conditions. Over the years, significant progress has been made in optimizing the culture conditions, establishing standardized protocols, and improving the characterization techniques for fish primary cell cultures. The review highlights the diverse cell types that have been successfully cultured from different fish species, including gonad cells, pituitary cells, muscle cells, hepatocytes, kidney and immune cells, adipocyte cells and myeloid cells, brain cells, primary fin cells, gill cells, and other cells. Each cell type exhibits distinct physiological functions, contributing to vital processes such as metabolism, tissue regeneration, immune response, and toxin metabolism. Furthermore, this paper explores the pivotal role of fish primary cell culture in elucidating the mechanisms underlying various physiological processes. Researchers have utilized fish primary cell cultures to study the effects of environmental factors, toxins, pathogens, and pharmaceutical compounds on cellular functions, providing valuable insights into fish health, disease pathogenesis, and drug development. The paper also discusses the application of fish primary cell cultures in aquaculture research, particularly in investigating fish growth, nutrition, reproduction, and stress responses. By mimicking the in vivo conditions in vitro, primary cell culture has proven instrumental in identifying key factors influencing fish health and performance, thereby contributing to the development of sustainable aquaculture practices.

Exposure effects of iron oxide nanoparticles and iron salts in blackfish (Capoeta fusca): Acute toxicity, bioaccumulation, depuration, and tissue histopathology

We assessed the toxicity of iron oxide nanoparticles compared with iron salts in the blackfish (Capoeta fusca). After an acute toxicity assessment, we conducted a chronic exposure to a sub-lethal concentration of Fe₃O₄ NPs, and iron salts (ferric nitrate (Fe(NO₃)₃), ferric chloride (FeCl₃), ferrous sulfate (FeSO₄)) to measure iron uptake over a period of 28 days and then subsequent clearance of the iron uptake in the exposed fish that were transferred to clean water for 28 days. Fe(NO₃)₃ was the most acutely toxic compound followed by FeCl₃, FeSO₄, and Fe₃O₄ NPs. Exposure to Fe₃O₄ NPs and iron salts induced histopathology anomalies in both gills and intestine that included aneurism, hyperplasia, oedema, fusion of lamellae, lamellar synechiae, and clear signs of necrosis (in the gills) and increases in the number of goblet cells, blood cell counts, and higher numbers of lymphocyte (in the intestine). Fe₃O₄ NPs showed a higher level of uptake in the body tissues compared with iron salts (p < 0.05) with levels of Fe in the gill > intestine > liver > kidney. Fe was shown to be eliminated most efficiently from the gills, followed by the kidney, then liver and finally the intestine. The highest tissue bioconcentration factors (BCF) occurred in the liver for FeCl₃, Fe₃O₄ NPs, and FeSO₄ and in the gills for Fe(NO₃)₃. We thus show differences in the patterns of tissue accumulation, clearance and toxicological responses for exposures to Fe₃O₄ NPs and iron salts in blackfish with implications for different susceptibilities for biological effects.

Impact of sediments resuspension on metal solubilization and water quality during recurrent reservoir sluicing management

In dam contexts, sluicing operations can be performed to reestablish sediments continuity, as proposed by the EU Water Framework Directive, as well as to preserve the reservoirs' water storage capacity. Such management permits the rapid release of high quantities of reservoir sediments through the opening of dam bottom valves. This work aims to study the impact of such operation on the evolution of environmental physicochemical conditions notably changes in dissolved metallic elements concentrations (Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn) through field and laboratory investigations. Results were interpreted in terms of concentrations and fluxes, and compared with data collected on an annual basis regarding both suspended matter and metallic elements. The release of high quantities of sediments (4,500tons dry weight in 24h), with concentrations representing up to 300 times the inter-annual mean suspended sediments discharge, significantly modified water parameters, notably solid/liquid (S/L) ratio, pH and redox conditions. Despite the fact that they are mainly trapped in stable phases, a clear increase of the solubilized metals content was measured, representing up to 60 times the maximum values of current exploitation. This solubilization is related to desorption phenomena from sediments through changes in chemical equilibriums as highlighted by laboratory characterizations and experiments. These chemical modifications are mainly attributed to S/L ratio variations. Indeed, the low S/L ratios (≤1.3g·L(-1)) measured in situ are typically the ones for which metals solubilization is the highest, as shown by laboratory experiments. Additional thermodynamic modeling highlighted that the decrease in pH measured during the operation favors the release of the free forms of metallic elements (Al and Cu), and decreases the OM complexation influence. These changes, either in term of physical conditions or speciation, increasing metals long term bioavailability notably during redeposition phase, may have adverse effects on aquatic biota.

Gill cell culture systems as models for aquatic environmental monitoring

A vast number of chemicals require environmental safety assessments for market authorisation. To ensure acceptable water quality, effluents and natural waters are monitored for their potential harmful effects. Tests for market authorisation and environmental monitoring usually involve the use of large numbers of organisms and, for ethical, cost and logistic reasons, there is a drive to develop alternative methods that can predict toxicity to fish without the need to expose any animals. There is therefore a great interest in the potential to use cultured fish cells in chemical toxicity testing. This review summarises the advances made in the area and focuses in particular on a system of cultured fish gill cells grown into an epithelium that permits direct treatment with water samples.