Methylmercury is a hazardous substance that is of interest with regard to environmental health, as inorganic mercury circulating in the general environment is dissolved into freshwater and seawater, condensed through the food chain, ingested by humans, and consequently affects human health. Recently, there has been much interest and discussion regarding the toxicity of methylmercury, the correlation with fish and shellfish intake, and methods of long-term management of the human health effects of methylmercury. What effects chronic exposure to a low concentration of methylmercury has on human health remains controversial. Although the possibility of methylmercury poisoning the heart and blood vessel system, the reproductive system, and the immune system is continuously raised and discussed, and the carcinogenicity of methylmercury is also under discussion, a clear conclusion regarding the human health effects according to exposure level has not yet been drawn. The Joint FAO/WHO Expert Committee on Food Additives proposed to prepare additional fish and shellfish intake recommendations for consumers based on the quantified evaluation of the hazardousness of methylmercury contained in fish and shellfish, methylmercury management in the Korea has not yet caught up with this international trend. Currently, the methylmercury exposure level of Koreans is known to be very high. The starting point of methylmercury exposure management is inorganic mercury in the general environment, but food intake through methylation is the main exposure source. Along with efforts to reduce mercury in the general environment, food intake management should be undertaken to reduce the human exposure to methylmercury in Korea.
Animals ; *Environmental Exposure ; Fishes/metabolism ; Food Chain ; Humans ; Mercury Poisoning, Nervous System/etiology ; Methylmercury Compounds/chemistry/*metabolism/toxicity ; Neurons/drug effects ; Oxidative Stress/drug effects ; Public Health ; Reproduction/drug effects ; Thymocytes/cytology/drug effects

BACKGROUNDCryptotanshinone (CT) is the major active constituent of Salvia miltiorrhiza Bunge. The present study was carried out to investigate the effects of CT on rats with adjuvant arthritis (AA).

METHODSAA was induced by the metatarsal footpad injection with complete Freund's adjuvant in male Sprague-Dawley rats. The secondary inflammatory reaction was evaluated by hind paw swelling and the polyarthritis index. Activity of interleukin-1 (IL-1) was detected by the concanavalin A-induced thymocytes proliferation assay. The lymphocytes proliferation and IL-2 production were assayed by 3-(4,5-2dimethylthiazal-2yl)2,5-diphenyltetrazoliumbromide (MTT) and activated mouse splenocytes proliferation, respectively.

RESULTSIntragastric administration of CT (50 and 100 mg/kg) significantly decreased secondary inflammatory reactions and increased the spleen and thymus index. There was a marked immunologic and inflammatory response in the AA model, which was accompanied by the decrease of thymocyte proliferation and IL-2 production as well as the increase of IL-1 production. CT apparently enhanced thymocyte proliferation and decreased IL-1 production in AA rats.

CONCLUSIONThese results indicate that CT may exert its anti-inflammatory and immunoregulatory effects through inhibiting lymphocyte proliferation and production of pro-inflammatory mediators.

Animals ; Arthritis, Experimental ; drug therapy ; immunology ; metabolism ; Cell Proliferation ; drug effects ; Interleukin-1 ; metabolism ; Interleukin-2 ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Phenanthrenes ; therapeutic use ; Rats ; Rats, Sprague-Dawley ; Thymocytes ; cytology ; drug effects ; metabolism