Tissue-Specific HSP70 Levels and Reproductive Physiological Responses in Fishes Inhabiting a Metal-Contaminated Creek

Abstract

The 70-kDa stress protein family (HSP70) plays important roles in a variety of physiological processes, including protein chaperoning, protection against apoptosis, steroidogenesis, and general cellular stress responses in vertebrate organisms, and has also been proposed as a biochemical marker of environmental stress, such as toxicant exposure. The objectives of this study were to determine HSP70 protein expression in head kidney, liver, gill, and ovarian tissues and to examine reproductive physiological responses in female fishes exposed chronically to sublethal metal concentrations. Female black bullhead (Ameiurus melas) and bluegill sunfish (Lepomis macrochirus) were collected from Tar Creek, Oklahoma (flowing through the Tri-State mining district) and from a nearby reference creek (Lytle Creek) during spring (prespawning; 26.5 +/- 0.95 degrees C water temperature) and winter (ovarian recrudescence; 4.8 +/- 0.80 degrees C water temperature). Aqueous (dissolved and suspended) concentrations of Cd and Zn and liver concentrations of Cd and Zn in both fish species were significantly greater at Tar Creek compared to Lytle Creek. HSP70 expression was consistently elevated in the head kidney of both fish species collected at Tar Creek in comparison to fish collected from the reference creek. In contrast, no consistent differences were observed in HSP70 expression in liver, gill, or ovarian tissues between sites. Significant seasonal differences were observed in expression of HSP70 in gill tissue of both species, in ovarian and liver tissue of bluegill sunfish and in head kidney of black bullhead. Serum testosterone concentration was significantly reduced in sunfish collected from Tar Creek during winter. Gonadosomatic and hepatosomatic indices were significantly lower in black bullhead collected from Tar Creek during spring, and condition factors were lower in black bullhead collected from Tar Creek during both spring and winter. There was no significant difference in the extent of ovarian follicular cell apoptosis in either species collected during spring. In conclusion, we observed significant tissue specific differences and seasonal variation in expression of HSP70, as well as alterations in circulating testosterone levels in female fish chronically exposed to metals.

A Screening-Level Assessment of Lead, Cadmium, and Zinc in Fish and Crayfish from Northeastern Oklahoma, USA

“…Preliminary analysis indicates some risk to birds from the consumption of Pb and Zn contaminated fish and invertebrates, but not Cd. This assessment is also consistent with recent reports of biochemical effects in fish Yoo & Janz, 2003) and of Zn poisoning in TSMD waterfowl (Beyer et al, 2004). Collectively, the results of this and the other investigations cited indicate that fish in the TSMD are also exposed to comparatively high concentrations of Pb, Cd, and Zn and possibly other elemental contaminants from mining.…”

Concentrations of Cadmium, Lead, and Zinc in Fish from Mining-Influenced Waters of Northeastern Oklahoma: Sampling of Blood, Carcass, and Liver for Aquatic Biomonitoring

“…Mean carp liver concentrations for our most elevated OK sites were about 2-3 times greater than the NAWQA geometric mean for Zn, about 5-7 times greater for Pb, and about 9-40 times greater for Cd. Interestingly, Yoo and Janz (2003) reported liver metal concentrations for bluegill sunfish (Lepomis macrochirus) collected from TC, OK that were similar to concentrations in our carp livers collected from the mouth of that stream (site 6). Although no carp were obtained from any NAWQA sites specifically associated with mining, the NAWQA carp liver maximum for Pb was similar to that in carp livers from OK site 6 and the BR.…”

“…In Jasper Co., MO, Cherokee Co., KS, and Ottawa Co., OK, there are unremediated sites contaminated to varying degrees by historical mining and ore-processing activities. Metals from these sites have contaminated surface waters, groundwater, stream sediments, and biota in parts of the Spring River (SR) and Neosho River (NR) and their tributaries (Allen and Wilson 1992;Barks 1977;Czarneski 1985;Davis and Schumacher 1992;Neuberger et al 1990;Spruill 1987;Wildhaber et al 2000;Yoo and Janz 2003). Relative to the MO and KS sections of the SR-NR system, study of aquatic resource contamination in OK has been limited.…”

Heavy metal contents in whitefish (Coregonus lavaretus) along a pollution gradient in a subarctic watercourse

“…Most of the studied metals are essential microelements (Nemova 2005), and homeostasis of these elements in the organism is supported by complex processes at the cellular level (Yoo and Janz 2003). However, an excess intake of metals may result in negative processes leading to both lethal and sub-lethal effects due to functional disorders of the organisms (Akimova et al 2000;Hollis et al 2000;Cooley et al 2002;Lukin et al 2003;Veltman et al 2008).…”