EFFECTS OF TRIBUTYLTIN (TBT) ON REDOX HOMEOSTASIS OF THE POSTERIOR GILLS OF THE BLUE CRAB CALLINECTES SAPIDUS

Resumo

INTRODUCTION: Tributyltin (TBT) has been widely used as a biocide in antifouling paints applied to boat hulls. Although its use has been banned due to its impacts on non-target organisms, its residues are still detected in aquatic environments. Currently, TBT is recognized as one of the most toxic anthropogenic pollutants ever introduced into the environment. Its toxicity affects several organisms, including the blue crab Callinectes sapidus. In crustaceans, posterior gills are the main site of osmoregulation. OBJECTIVE: Investigate the effects of TBT on oxidative homeostasis in the posterior gills of C. sapidus. MATERIALS AND METHODS: The crabs were collected in Tramandaí/RS, transported to the laboratory and kept for acclimation for seven days. For the experiment, they were divided into three groups: control, 100 ng.L-1 and 1000 ng.L-1 of TBT. After seven days of exposure, the animals were cryoanesthetized and their posterior gills were collected for oxidative parameter analysis. The data were analyzed by Kruskal-Wallis followed by Dunn for nonparametric variables and ANOVA followed by Tukey for parametric variables, considering significance of plt;0.05. RESULTS: Total protein concentration was significantly lower in both groups exposed to TBT compared to the control group (100 ng.L-1: p= 0.033; 1000 ng.L-1: p= 0.004). Total ROS levels increased in the 1000 ng.L -1 TBT group when compared to the 100 ng.L-1 group (p= 0.026). In both groups exposed to TBT, sulfhydryl content decreased (100 ng.L-1: p=0.0007; 1000 ng.L-1: p=0.0047) compared to the control group. TBARS levels were higher in the 1000 ng.L-1 TBT group compared to the control (p= 0.032). Total GSH levels decreased in both groups exposed to TBT when compared to the control (100 ng.L-1: p=0.0016; 1000 ng.L-1: p=0.0043). GST activity increased (p=0.0071) in crabs exposed to 100 ng.L-1 TBT when compared to the control group. CONCLUSION: The data indicate an impact of TBT on oxidative homeostasis, which may compromise posterior gills function. Further studies are needed to better understand the effects of this contaminant on blue crabs.