Biochemical metal accumulation effects and metalloprotein metal detoxification in environmentally exposed tropical Perna perna mussels.

Marine bivalves have been widely applied as environmental contamination bioindicators, although studies concerning tropical species are less available compared to temperate climate species. Assessments regarding Perna perna mytilid mussels, in particular, are scarce, even though this is an extremely important species in economic terms in tropical countries, such as Brazil. To this end, Perna perna mytilids were sampled from two tropical bays in Southeastern Brazil, one anthropogenically impacted and one previously considered a reference site for metal contamination. Gill metallothionein (MT), reduced glutathione (GSH), carboxylesterase (CarbE) and lipid peroxidation (LPO) were determined by UV-vis spectrophotometry, and metal and metalloid contents were determined by inductively coupled plasma mass spectrometry (ICP-MS). Metalloprotein metal detoxification routes in heat-stable cellular gill fractions were assessed by size exclusion high performance chromatography (SEC-HPLC) coupled to an ICP-MS. Several associations between metals and oxidative stress endpoints were observed at all four sampling sites through a Principal Component Analysis. As, Cd, Ni and Se contents, in particular, seem to directly affect CarbE activity. MT is implicated in playing a dual role in both metal detoxification and radical oxygen species scavenging. Differential SEC-HPLC-ICP-MS metal-binding profiles, and, thus, detoxification mechanisms, were observed, with probable As-, Cu- and Ni-GSH complexation and binding to low molecular weight proteins. Perna perna mussels were proven adequate tropical bioindicators, and further monitoring efforts are recommended, due to lack of data regarding biochemical metal effects in tropical species. Integrated assessments, as performed herein demonstrate, are invaluable in evaluating contaminated aquatic environments, resulting in more accurate ecological risk assessments.

Anti-arthritic properties of crude extract from Chenopodium ambrosioides L. leaves.

OBJECTIVES: To evaluate the effect of hydroalcoholic crude extract (HCE) from Chenopodium ambrosioides leaves on the development of type II collagen-induced arthritis (CIA) and on pro-inflammatory cytokine balance. METHODS: Collagen-induced arthritis was induced in DBA1/J mice. On the 21st day, the mice were treated orally with HCE or methotrexate, daily. Six weeks after beginning the treatment, the following measures were determined: lymphoid organs cell numbers, percentage of blood cells, IL-6, IFN-γ, TNF-α and IL-17 serum concentrations, activity of hepatic and kidney glutathione S-transferase, hepatic 7-ethoxyresorufin-O-deethylase activity, bone density and histopathology. KEY FINDINGS: Treatment of CIA mice with HCE 5 mg/kg (HCE5) reduced the percentage of neutrophils and macrophages and the number of bone marrow cells and increased the lymphocyte numbers and the inguinal lymph node cellularity. This treatment inhibited the serum concentration of IL-6 and TNF-α, which may be related to the preservation of bone density and to the slight thickening of periarticular tissues, with minimal fibrosis and fibroblast proliferation in the joints. The CIA group presented advanced articular erosion and synovial hyperplasia. Phytochemical analysis showed mainly flavonols. CONCLUSIONS: HCE5 presented anti-arthritic potential and reduced IL-6 and TNF-α, which participate directly in the development and maintenance of the inflammatory process in rheumatoid arthritis.

Bile and liver metallothionein behavior in copper-exposed fish.

The present study analyzed metallothionein (MT) excretion from liver to bile in Nile Tilapia (Oreochromis niloticus) exposed to sub-lethal copper concentrations (2mgL(-1)) in a laboratory setting. MTs in liver and bile were quantified by spectrophotometry after thermal incubation and MT metal-binding profiles were characterized by size exclusion high performance liquid chromatography coupled to ICP-MS (SEC-HPLC-ICP-MS). Results show that liver MT is present in approximately 250-fold higher concentrations than bile MT in non-exposed fish. Differences between the MT profiles from the control and exposed group were observed for both matrices, indicating differential metal-binding behavior when comparing liver and bile MT. This is novel data regarding intra-organ MT comparisons, since differences between organs are usually present only with regard to quantification, not metal-binding behavior. Bile MT showed statistically significant differences between the control and exposed group, while the same did not occur with liver MT. This indicates that MTs synthesized in the liver accumulate more slowly than MTs excreted from liver to bile, since the same fish presented significantly higher MT levels in liver when compared to bile. We postulate that bile, although excreted in the intestine and partially reabsorbed by the same returning to the liver, may also release MT-bound metals more rapidly and efficiently, which may indicate an efficient detoxification route. Thus, we propose that the analysis of bile MTs to observe recent metal exposure may be more adequate than the analysis of liver MTs, since organism responses to metals are more quickly observed in bile, although further studies are necessary.