Journal of Endocrinology and Reproduction

R. N. Binitha ¹, S. R. Soorya ¹, C. Aruna Devi ¹, Francis Sunny ¹

Affiliations
1 Department of Zoology, University College, Palayam, Trivandrum-695034, Kerala, IN

Abstract

This study investigated the impact of sewage effluents of the polluted river, Parvathyputhenar in Trivandrum city, Kerala, India, on the activities of osmoregulatory enzymes such as Na⁺/K⁺ and Ca²⁺ ATPases, the concentration of sodium and potassium ion content in the gill and on the chloride cells (CCs) and pavement cells (PCs) that regulate ions transport in the gill epithelium of a freshwater fish. The results indicate a significant (P<0.05) decrease in the activity of branchial Na⁺/K⁺ ATPase and Ca²⁺ ATPase in the fish exposed to sewage effluents for 7, 14 and 28 days and the fish caught from the polluted river. When the fish caught from the polluted river were kept in normal pond water in the laboratory for 30, 60 and 90 days, the enzyme's activities were gradually increased and almost restored to the control level. Scanning electron microscopic analysis of gill epithelium showed noticeable changes in the surface area morphology of CCs and PCs in the fish exposed to sewage effluents. Exposure to the sewage effluents drastically altered the size and characteristic "finger print" pattern of PCs and also reduced number of CCs in the gill epithelium. As the ATPases play an important role in maintenance of functional integrity of gill epithelium it is suggested that measurement of the activities of ATPases may be used as a biomarker of exposure to sewage effluents. This work is highly pertinent in the context of increased level and effect of endocrine disrupting chemicals present in the aquatic systems, which are increasing day by day.

Keywords

Sewage Effluents, Na⁺/K⁺ ATPase, Ca²⁺ ATPase, Chloride Cells, Pavement Cells.

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C. Aruna Devi ¹, R. N. Binitha ¹, S. R. Soorya ¹, B. V. Amrutha ¹, Francis Sunny ¹

Affiliations
1 Department of Zoology, University College, Thiruvananthapuram-695034, Kerala, IN

Abstract

Bisphenol-A (BPA), an industrial chemical used to manufacture polycarbonate plastic, is considered as a potent estrogenic endocrine disruptor. A majority of xenobiotics exert their toxic effect by causing generation of reactive oxygen species, leading to oxidative stress. Reports regarding oxidative stress responses to BPA in fish are scanty. From this viewpoint, in the present study, a freshwater fish, Anabas testudineus, was exposed to sub-lethal concentrations of BPA (2.5, 5.0,&7.5 mg/l), for different time periods (7, 15&30 days). Four major enzymes of the fish's antioxidant defense system viz., catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (Se-GPx), and glutathione-S-transferase (GST), and the non-enzymatic antioxidant glutathione (GSH) were chosen as biomarkers to examine the effects of BPA. The activities of SOD, GPx and GSH were elevated to significant levels, while CAT and GST activities were decreased significantly suggesting oxidative stress in BPAexposed fish. Reactive oxygen species are known to cause DNA fragmentation. Hence, DNA fragmentation assay was also done. The severity of DNA fragmentation in fish exposed to 7.5 mg/L BPA (30days) was remarkably increased (p<0.05 vs control) and this was revealed in gel electrophoresis analysis also. The results clearly show that BPA is a pollutant with oxidative potential, also with a potential for DNA fragmentation. The potential risks of this compound to nature and human populations are significant since the production of BPA related compounds is increasing dramatically each year.

Keywords

Endocrine Disruptor, Oxidative Stress, DNA Fragmentation, BPA, Antioxidants.

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