Biomarcadores histológicos, enzimáticos e expressão gênica de glutationa S-transferase e catalase em Sciades herzbergii (Bloch, 1794, Pisces, Ariidae) para o monitoramento de impactos antrópicos na Baía de São Marcos-MA

Abstract

The objective of the present study was to evaluate histological, enzymatic and gene expression biomarkers of glutathione S-transferase (GST) and catalase (CAT) in fish of the species Sciades herzbergii (Bloch, 1794), collected under the area of industrial and port influence and an area of environmental preservation in the Bay of São Marcos, Maranhão. Specimens of S. herzbergii (Bloch, 1794), were collected every six months between 2019 and 2021 (March and July) at two times of the year (rainy and dry) in São Marcos Bay: Porto Grande (PG), a potentially impacted region; and Ilha dos Caranguejos (IC), an area with the lowest impact. Sediment samples were collected for chemical analysis of trace metals and polycyclic aromatic hydrocarbons (PAHs). Morphometry, GST and CAT enzyme activity, and branchial and hepatic alterations (for the two years of the study) and GST and CAT gene expression (for 2021) were analyzed for each specimen. The results of the HPA analyses of the sediments showed that in the PG region the concentrations were significantly (p<0.05) higher compared to IC. Most of the trace elements present in the sediments were in accordance with the levels recommended by the Brazilian regulatory standards. Al, Fe, Mn and Sr showed differences between the sampled sites with higher values. The morphometric data of CI fish in the rainy season showed a high average of weight and size compared to PG for the two years of collections. The alterations in the gills of the fish identified in HF were: lamellar fusion, epithelial displacement and tissue degeneration. In PG, the following parameters were: epithelial displacement, lamellar fusion, necrosis and hyperplasia. The changes in the liver observed were: fibrosis, necrosis and melanomacrophage centers in both areas. GST and CAT activities in gills and livers of fish from HF showed high averages in the rainy season in 2019. In 2021, GST and CAT in gills and liver of fish also showed higher averages in the rainy season in PG. The gene expression of GST and CAT were not expressed in gills and livers of fish in

PG and IC for this study. However, in this study, the expression of the endogenous genes Beta- actin, 18S ribosomal RNA, 28S ribosomal RNA in gills and livers of S. herzbergii (Bloch, 1794)

was identified for the first time, indicating the quality of the biological material. The results of the selected biomarkers (enzymatic and histological) suggest that the fish in both areas are responding negatively to the impacts on the environment, especially the fish caught in PG, which demonstrate more significant changes. Endogenous genes (Beta-actin, 18S ribosomal RNA, 28S ribosomal RNA) showed positive responses indicating the reliability of the method applied to S. herzbergii (Bloch, 1794). The histological, enzymatic and gene expression biomarkers of GST and CAT in S. herzbergii (Bloch, 1794) were able to differentiate the quality and impacts from two areas of São Marcos Bay, Maranhão.