BACKGROUND: Exposure to methylmercury (MeHg) is predominantly attributed to consumption of marine products. However, the general population is exposed to low MeHg levels, which can induce chronic inflammation. Although some MeHg-related microRNAs (miRNAs) have been reported, their functions remain elusive. The objective of this study was to identify the miRNAs induced by low-level MeHg exposure in a human endothelial cell line (HAECs). This study aimed to determine the specific miRNAs induced by low-level MeHg exposure using a HAECs as a potential novel and sensitive biomarker. The roles of miRNAs in inflammatory processes have been examined. METHODS: Using HAECs, a miRNA microarray assay was performed to identify miRNAs with altered expression upon exposure to a non-cytotoxic MeHg level (0.1 and 1.5 µM). The expression patterns of interleukin-6 and -8, cyclooxygenase 2 (COX-2), RelB, and prostaglandin E₂ (PGE₂) were examined after transfection of the identified miRNAs with mimics/inhibitors. RESULTS: Although the microarray assay identified six MeHg-specific miRNAs, miR-3613-5p, upregulated by 0.1 and 1.5 µM MeHg exposures, demonstrated the best reproducibility in HAECs. Transfection with the miR-3613-5p mimic enhanced the MeHg-induced inflammatory responses, including PGE₂ and COX-2 protein levels, whereas the miR-3613-5p inhibitor suppressed these inflammatory responses. CONCLUSION This study observed that miR-3613-5p is induced by low-dose MeHg exposure, plays a crucial role in the inflammatory process, and could serve as a novel and sensitive biomarker for low-level MeHg exposure.
Methylmercury Compounds/adverse effects* ; Humans ; MicroRNAs/genetics* ; Endothelial Cells/metabolism* ; Inflammation/genetics* ; Cell Line ; Aorta/drug effects* ; Biomarkers/metabolism*

OBJECTIVETo compare sub-acute toxic effects of cinnabar and Wansheng Huafeng Dan with mercury chloride and methyl-mercury.

METHODHealthy SD rats were orally administered with Wansheng Huafeng Dan (0.42 g x kg(-1)), cinnabar (0.15 g x kg(-1)), HgS (0.15 g x kg(-1)), HgCl2 (0.02 g x kg(-1)), MeHg (0.001 g x kg(-1)) and saline for 21 days under observed and their weights were monitored. After the final administration, they were decapitated and their blood, liver, kidney and brain tissues were collected for calculating hepatic and renal indexes and detecting the contents of serum glutamic pyruvic transaminase, urea nitrogen and creatinine and the mercury accumulation in liver, kidney and brain tissues. Besides, relative expressions of liver metallothionein-1 (MT-1) and cytochrome P450 gene subtypes (Cyp1a1, Cyp2b1, Cyp2e1, Cyp3a2, Cyp4a10) mRNA.

RESULTHgCl2 caused obvious weight lose in rats. Mercury contents in liver and kidney were markedly increased by HgCl2 and MeHg, and MeHg markedly increased mercury contents of brain either, but these advent effects were not notable in Wansheng Huafeng Dan and cinnabar groups. However, blood biochemistry and histopathology did not show significant changes in all groups. The expression of rat hepatic MT-1 mRNA was remarkably induced by both HgCl2 and MeHg. The expression of hepatic Cyp3a2 was increased by Wansheng Huafeng Dan and cinnabar, while the expression of Cyp2e1 was inhibited by HgCl2 and MeHg.

CONCLUSIONThe administration of Wansheng Huafeng Dan with equivalent dose for three weeks shows a much low sub-acute toxicity than HgCl2 and MeHg in rats.

Administration, Oral ; Animals ; Brain ; drug effects ; Drugs, Chinese Herbal ; administration & dosage ; adverse effects ; Kidney ; drug effects ; Liver ; drug effects ; Male ; Mercuric Chloride ; toxicity ; Mercury Compounds ; toxicity ; Methylmercury Compounds ; toxicity ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the toxicity of Cinnabar and Cinnabar-containing traditional medicines (Zhusha Anshenwan) comparable to common mercurials.

METHODThe toxicity of methylmercury (MeHg), mercuric chloride (HgCl2), Cinnabar and Zhusha Anshenwan was studied in cultured human liver HL-7702 cells and in mice following acute and subacute exposures.

RESULTThe 50% lethal concentrations (LC50) of MeHg, HgCl2, Cinnabar and Zhusha Anshenwan in human liver HL-7702 cells were 4.4, 9.2, 2460, 4050 mg x L(-1), respectively . Oral cinnabar at a dose of 20 g x kg(-1) (clinical dosage 250 times) did not kill mouse, but no mouse could survive MeHg at a dose of 0.1 g x kg(-1) or HgCl2 at a dose of 0. 15 g x kg(-1). Subacute toxicity experiment indicated that HgCl2 retarded body weight gain with significant accumulation of Hg in the liver and kidney. In comparison, mercury accumulation after Cinnabar and Zhusha Anshenwan was insignificant. No apparent hepatic and renal dysfunctions were evident under the experimental conditions, but the metallothionein-2 mRNA levels were much higher in HgCl2 group than in other groups.

CONCLUSIONCinnabar and Zhusha Anshenwan are much less toxic than MeHg and HgCl2.

Animals ; Female ; Gene Expression ; drug effects ; Kidney ; drug effects ; physiology ; Liver ; drug effects ; physiology ; Male ; Mercuric Chloride ; administration & dosage ; adverse effects ; Mercury Compounds ; administration & dosage ; adverse effects ; Methylmercury Compounds ; administration & dosage ; adverse effects ; Mice ; Mice, Inbred BALB C ; Random Allocation

OBJECTIVETo study the oxidative stress induced by consumption of mercury-contaminated rice in rats, and to assess the possible public health risk of mercury contamination in Wanshan mining area.

METHODSSprague Dawley rats were fed the mercury-contaminated rice produced from Wanshan area for 90 days. The antioxidant status and the free radicals in rat serum were evaluated.

RESULTSHigh mercury accumulation in organs of rats fed the mercury-contaminated rice confirmed the server pollution of mercury in Wanshan mining area. The intensity of electron spin resonance (ESR) signal increased by 87.38% in rats fed the rice from Wanshan compared with that in the control rats fed the rice from Shanghai, suggesting that chronic dietary consumption of rice from mercury mining area could induce an aggravation of free radicals. Feeding the mercury-contaminated rice was associated with significant decreases in the antioxidant enzymatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and concentration of serum nitric oxide (NO), but it had no effect on serum nitric oxide synthase (NOS) activity. Feeding the mercury-contaminated rice raised the level of serum malonyldialdehyde (MDA), indicating the occurrence of oxidative stress.

CONCLUSIONThe long-term dietary consumption of mercury-contaminated rice induces the aggravation of free radicals and exerts oxidative stress.

Animals ; Brain ; metabolism ; China ; Environmental Pollutants ; analysis ; pharmacokinetics ; toxicity ; Food Contamination ; analysis ; Free Radicals ; blood ; Glutathione Peroxidase ; blood ; Industrial Waste ; adverse effects ; Kidney ; metabolism ; Liver ; metabolism ; Malondialdehyde ; blood ; Mercury ; analysis ; pharmacokinetics ; toxicity ; Methylmercury Compounds ; analysis ; pharmacokinetics ; toxicity ; Nitric Oxide ; blood ; Nitric Oxide Synthase ; blood ; Oryza ; Oxidative Stress ; Rats ; Rats, Sprague-Dawley ; Superoxide Dismutase ; blood

OBJECTIVETo study the DNA damage induced by methylmercury (MeHg) in mouse hepatocytes.

METHODSThe single cell gel electrophoresis (SCGE) was used to study the DNA damage of mouse hepatocytes when treated with different doses in vivo and in vitro.

RESULTSAfter treated with high, middle and low doses of MeHg for 12 h in vivo (i.p.), the proportion of DNA damage was increased and the ratio of living cells was decreased; and both effects showed significantly dose-effect relationships. Similar effects were found when different MeHg doses were administered to hepatocytes in vitro for 1 h.

CONCLUSIONMeHg induces DNA damage in mouse hepatocytes.

Animals ; Cell Survival ; drug effects ; Cells, Cultured ; DNA Damage ; Hepatocytes ; cytology ; drug effects ; Liver ; cytology ; drug effects ; Male ; Methylmercury Compounds ; adverse effects ; Mice