The Combined Toxicity Research Of Melamine And Cyanuric Acid

In the spring of2007, large acute renal failures of cats and dogs associated with food contamination broke out in North America. By the end of March, there had at least471cases of kidney failure been reported in a10-perild, and104dogs and cats had died. Subsequent investigations indicated that the contaminated pet foods were adulterated intentionally with melamine (MEL) and MEL-related compounds, including cyanuric acid (CYA). Not come singly but in pairs, in September2008, a fresh outbreak of kidney disease occurred, due to baby formula contaminated by melamine. Six babies died and294,000were made sick by the tainted formula with51,900requiring hospitalization. The increasingly melamine adulteration result in renal failure incidences have made Melamine and cyanuric acid become notorious.In this study, we assessed the combined toxicity of melamine and cyanuric acid in both vivo and vitro. In vivo, we conducted the combined acute toxicity assay and bone marrow micronucleus test. In vitro, the influence of melamine and cyanuric acid compound(M+C) to293Ad5+cells and L02hepar cells viability were tested, and kidney injury molecule1(Kim-1) expression levels of293Ad5+cells was studied at the same time.Karber has been used to explore the combined acute toxicity of melamine and cyanuric acid compound(M+C). Three ratios of M+C were infused with the spray by single oral injection into mice. Six dose groups were treated in each proportion, for109,173,274,435,689and1092mg/kg, respectively, and orally capacity was0.02ml/g. The solvent control received same volume of corn oil and blank control group was not treated. Results: M+C (1:1) group, LD50of male mice was274mg/kg, LD50of female mice was401mg/kg; M+C (2:1) group, LD50of male mice was401mg/kg, LD50of female mice was546mg/kg; M+C (1:2) group, LD50of male mice was344mg/kg, LD50of female mice was589mg/kg. The lethal dose of M+C compounds was1092mg/kg, and the non-fatal dose was173mg/kg. The necropsy of died animals showed kidneys of treatment group were enlarged. Auto lysis and multiple golden brown spots were noted on the surface of the kidneys. Organ coefficients of kidney in each drugged group visibly increased by comparison to two control groups, and the difference has statistically significant(P<0.05).The possible clastogenic activity of M+C was assessed in vivo mouse bone marrow micronucleus test following double Oral gavage24h apart. Each proportions of melamine and cyanuric was tested in three doses approximating1/2,1/4and1/8of the LD50-values. Results:there was no significant increase of micronuclei among the groups treated with different ratio and dose of M+C and the negative control group(P>0.05). The results had come up negative for test materials.MTT assay was used to measure MC cytotoxicity to293Ad5+cells and L02hepar cells, melamine and cyanuric acid in three ratios of1:1,2:1and1:2were mixed, the concentration was0,5.1,10.3,20.6,41.2,82.5and165μg/ml. Results:For MC(1:1), MC(1:2) and MC(2:1), a slightly increase of the activity was observed at low dose group, followed by different decrease in activity as the concentration of the compound increased,and293Ad5+cells and L02hepar cells share the same tendency.All the MC treatment groups at165μg/ml dose have negative effects on293Ad5+and L02hepar cells viability.Western blot were used to investigate expression of Kim-1when293Ad5+cells treated with MC(1:1). According to MTT assay results, the test melamine and cyanuric acid in a1:1mass ratio, the concentration of5.165,82.5and165μg/ml, and set blank group. Results:expression of Kim-1was significantly increased in82.5μg/ml and41.25μg/ml dose group, and the difference has statistically significant(cmpared control group P<0.05). In low dose of20.625μg/ml group, Kim-1expression levels showed no significant difference compared with control group (P>0.05).