The Change of Metallothionein and Oxidative Response in Gills of the Oreochromis niloticus after Exposure to Copper.

Faridlotul Ma’Rifah,Bambang Irawan,Miftahul Rohmah Saputri,Agoes Soegianto,Trisnadi Widyaleksono Catur Putranto

doi:10.3390/ani9060353

Faridlotul Ma’Rifah, Bambang Irawan + Show 3 more

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https://doi.org/10.3390/ani9060353

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Abstract

Simple SummaryCopper is an essential element for the aquatic organisms for a number of biological processes. However, it may be toxic at high concentrations. The present study revealed that the levels of Cu in gills of all Cu-exposed tilapia significantly increased during the first few days, and then gradually decreased, matching the control at D4-D5. The concentration of metallothionein (MT) and the activities of superoxide dismutase (SOD) and catalase (CAT) in the gills of Cu-exposed fish were in line with the accumulated Cu. The increase of MT, SOD, and CAT during the first few days might be the adaptive response of the animal to Cu toxicity. MT binds the elevated Cu, while SOD and CAT scavenge the increased free radicals due to the increasing level of Cu. Cu does not affect the malondialdehyde (MDA) concentration in gills of fish, which suggests the SOD, CAT and MT as antioxidant defense systems were able to completely scavenge the increased free radicals.In the present study, we investigated the effects of waterborne copper (Cu) on the levels of metallothionein (MT) and malondialdehyde (MDA), as well as activities of superoxide dismutase (SOD) and catalase (CAT) in gills of cichlid fish Oreochromis niloticus. The Cu concentrations in gills were measured using an atomic absorption spectrometer. The sandwich-ELISA was used to measure MT, SOD, CAT, and MDA. The Cu concentrations in gills of fish that were exposed to 1, 5, and 10 mg Cu/L were significantly increased at day 1 (D1), then gradually decreased starting from D2, and reaches the similar value with the controls at D5. A similar tendency has been observed in the MT levels in the gills. All of the Cu-exposed fish showed the highest level of MT on D1, and then decreased at D3 and a plateau at D4 and D5. The levels of SOD and CAT in gills in all Cu-exposed fish showed a similar pattern: increased significantly at D1, then gradually decreased starting from D2, and increased again at D4 and D5. The levels of MDA in gills of all Cu-exposed fish showed no significant difference. The indifference levels of MDA in gills of all Cu-exposed fish suggested the antioxidant defense systems (SOD and CAT) combined with the induction of MT were able to completely scavenge the increased ROS.

Highlights

Copper is commonly found in aquatic systems as a result of both natural, and anthropogenic sources [1]
We investigated the concentrations of MT and MDA, as well as the activities of superoxide dismutase (SOD) and CAT in the gills of fish Oreochromis niloticus after exposure to waterborne copper
When compared to the control group, the Cu concentrations in gills of all Cu-exposed fish were significantly increased at day 1 (D1), gradually decreased starting from D2 to D4, and its concentration reaches the same value with the control at D5

Summary

Introduction

Copper is commonly found in aquatic systems as a result of both natural (such as geological deposits, volcanic activity, weathering and erosion of rocks and soils), and anthropogenic sources (such as mining activities, agriculture, metal and electrical manufacturing, and pesticide use) [1]. Copper is an essential element for aquatic organisms, including fish [8,9]. It can be utilized by a number of processes, such as cellular respiration, iron oxidation, pigment formation, connective-tissue biogenesis, peptide amidation, neurotransmitter biosynthesis, and free-radical defense and cellular metabolism [10,11]. Cu is a very toxic element when its cellular level is elevated [11,12].

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