Immune-Regulatory Transcriptional Responses in Multiple Organs of Atlantic Salmon After Tributyltin Exposure, Alone or in Combination with Forskolin

Abstract

Tributyltin (TBT) is a widespread marine pollutant that influences physiological conditions of fish and other aquatic organisms. In addition to effects on reproduction, the immune system has been proposed as a possible target for TBT effects. In the present study, the effects of TBT exposure were examined on the expression of genes involved in immune system compentence in liver and head kidney of Atlantic salmon, in the presence and absence of a second-messenger activator (forskolin). Juvenile salmon were force-fed a diet containing TBT (0-solvent control, 0.1, 1, or 10 mg/kg fish) for 72 h. Consequently, fish from the control group and 10-mg/kg TBT group were exposed to the adenylate cyclase (AC) activator forskolin (200 μg/L) for 2 or 4 h. Forskolin was selected for this study because it is known to exhibit potent immune system enhancement by activating macrophages and lymphocytes. After sacrifice, liver and head kidney were sampled and transcript changes for interleukin (IL)-1β, IL-10, transforming growth factor (TGF) β, interferon (INF) α, INFγ, tumor necrosis factor (TNF) α, Mx3, and insulin-like growth factor (IGF)-1 were determined in both tissues by quantitative polymerase chain reaction (qPCR) using gene-specific primers. TBT, when given alone and also in combination with forskolin, decreased IL-1β, TNFα, IFNγ, IFNα, Mx3, and IGF-1 gene expression. In contrast, IL-10 and TGFβ transcripts were increased after TBT exposure alone and also in combination with forskolin. Generally, these effects were largely dependent on TBT dose and time of exposure when given in combination with forskolin. Overall, our findings suggest a possible immunomodulatory effect of TBT, possibly involving cAMP activation.

Histological study of the effect of tributyltin on the adrenal cortical cells of adult male albino rats.

“…Generally, high levels of TGFβ1 lead to reduced plasma aldosterone and corticosterone levels. The data reported that TGF-β1 transcripts were increased after TBT administration [42,43] .…”

Effects of Fish Meal Replacement by a Soybean Protein on Growth, Histology, Selected Immune and Oxidative Status Markers of Gilthead Sea Bream, Sparus aurata

“…Increased levels of RBA at BS20 and BS40 groups in HK could be related with the increased levels of TGF‐β 1 . Studies concerning TGF‐β 1 expression in fish support that it functions as an immunosuppressive agent antagonizing pro‐inflammatory events, possibly by downregulating expression of other cytokines or cytokine‐induced effects to re‐establish immune homeostasis (Jang et al ; Pavlikova and Arukwe ). On the other hand, β2m is involved in antigen presentation required for production of antibodies and has been reported to be regulated by diet (Murray et al ).…”

IL10, A Tale of an Evolutionarily Conserved Cytokine across Vertebrates

“…This immunosuppressive effects have been linked to an increased expression of IL10 and TGF caused by this pollutant in Atlantic salmon. 119 An increase in serum IL10 was found in an experimental handling stress model in goldfish. In this study IL10 levels are proposed as an additional stress indicator together with cortisol and glucose levels.…”