Comparative bioaccumulation and effects of purified and cellular extract of cylindrospermopsin to freshwater fish Hoplias malabaricus.

Many tropical freshwater ecosystems are impacted by cyanobacteria blooms increasing the risk of cyanotoxins exposure to aquatic organisms while human populations may be exposed by eating fish, drinking water, or dermal swimming. However, few toxicological data are available on the influence of cyanobacteria blooms in particular, cylindrospermopsin (CYN) on Brazilian neotropical fish. A number of studies demonstrated the ability of CYN to bioaccumulate in freshwater organisms and consequently enter the human food chain. The aim of the current study was to examine the effects of CYN following single intraperitoneal injection (50 µg/kg) of purified CYN (CYNp) or aqueous extract of CYN-producing cyanobacteria extract (CYNex) after 7 or 14 days. Biomarkers such as histopathology (liver), oxidative stress (liver and brain), and acetylcholinesterase (AChE) activity (muscle and brain) were utilized in order to assess the influence of CYN on Hoplias malabaricus. In terms of AChE activity, administration of CYNex and CYNp both muscle and brains were used as target tissues. In brain an increase of glutathione S-transferase (GST) activity and lipid peroxidation (LPO) levels was noted suggesting an imbalance in redox cycling. The majority of biomarkers did not present significant alterations in liver, but an elevation in superoxide dismutase (SOD) and glucose 6 phosphate dehydrogenase (G6PDH) activities was found. Different profiles of GST activity were observed in both studied groups (CYNex and CYNp) while LPO (CYNex and CYNp) and protein carbonylation (PCO) (CYNp) levels increased after exposure to CYN. The incidence of necrosis, melanomacrophages centers, and free melanomacrophages were detected as evidence of cell death and immune responses. Nonprotein thiols (NPT) levels were not markedly affected in both exposed groups. Data demonstrated that in vivo exposure to CYN produced biochemical and morphological disturbances in liver and brain of H. malabaricus.

Characterization, specificity and sensibility of produced anti-Rhamdia quelen vitellogenin in Brazilian fish species.

Endocrine-disrupting chemicals (EDCs) are widespread used and can interfere on hormone regulation with adverse consequences for both biota and human. Vitellogenin (vtg) is a yolk precursor protein synthesized by the liver in response to estrogen. In order to characterize the vtg of tropical fish Rhamdia quelen and establish a molecular biomarker, adult male individuals were exposed to 17-ß-estradiol (E2) for vtg induction and anti-R. quelen vtg polyclonal antibodies production. Vitellogenic female fish were used as positive control group. E2-induced vtg was characterized as a glycolipophosphoprotein of high molecular mass with peptide mass fingerprint very similar in E2-exposed male and vitellogenic female fish. A polyclonal serum containing anti-R. quelen vtg antibodies was produced and showed high specificity and sensibility to detect the vtg of three fish species: R. quelen, Piaractus mesopotamicus and Prochilodus lineatus. Wildlife and laboratory studies reported that EDCs released into the environment may alter the levels of plasma vtg in male fish, making this protein a valuable biomarker of xenoestrogens exposure. Then, we propose the use of anti-R. quelen vtg as a tool for biomonitoring studies and water quality assessment in Brazil and South American countries where the three fish species occur.

Testicular effects following in utero exposure to the antivirals acyclovir and ganciclovir in rats.

In utero exposure to the antivirals acyclovir and ganciclovir has been reported to induce gross structural defects in rat offspring. The present study investigated the effects of maternal antiviral treatment on gestation day 10 on reproductive and nonreproductive organs in male rat offspring with a particular focus on the testes. Vehicle and two doses of acyclovir and ganciclovir, 75 and 300 mg/kg, were administered to rat dams. The total doses were fractioned into three subcutaneous applications (3 × distilled water, 3 × 25 mg/kg, and 3 × 100 mg/kg) that were administered on gestation day 10 at 8:00 a.m., 1:00 p.m., and 6:00 p.m. The antiviral concentrations were measured in the serum of the dams 1 h after the last administration. Exposure to 300 mg/kg ganciclovir induced germ cell deficiency in both fetal and adult testes, an effect that was not seen in any other treatment group. Adult rats exposed in utero to this high ganciclovir dose exhibited Sertoli cell-only tubules intermingled with seminiferous tubules that displayed a normal size and normal cell counts, alterations that resemble focal Sertoli cell-only syndrome in humans. The serum concentrations of ganciclovir were markedly higher than those of acyclovir, particularly at the high dose tested. However, although 300 mg/kg acyclovir did not induce germ cell deficiency, other specific effects were seen in exposed animals, including incomplete eye opening and reduced thymus weight.