Study On Methyl-mercuric Chloride Distribution And Amino Acids Influencing On Brain Mercury Contents In Rat Vivo

Environmental pollution originated methyl mercury is a very severe issue inthe global.Many scholars in the world have research methyl mercury toxiceffect and mechanism since the recent 50 years.Some researches havedemonstrated methyl mercury toxicokinetics by animal trial which is thatmethyl mercury is maldistribution and may permeate blood brain barrier invivo. brain tissue is the most sensitive to methyl mercury toxic effect whichcan lead to nervous system injury. Many factors may influence on methylmercury distribution in the brain.This study aims at investigating methylmercury distribution in vivo when giving inferior toxic dose to the rats andweight changes, organes weight changes and histopathology changes whengiving toxic dose to the rats.Then, we explored brain mercury contents whengiving both toxic dose methyl mercury and acidic, neutral and basic aminoacid.1. Methyl-mercuric chloride distribution in vivo Total mercury contents of organs in the trial group are obviously higher thanin the control group. Total mercury contents in the brain, liver and kidney wereall gotten to the summit in the tenth day and the summit of the blood is thefifth day.After this, total mercury contents in the both organs and blood beganfall-off. Methyl-mercuric chloride distribution in rat vivo: kidney>liver>brain.2.Experimental animal model and amino acids influence on brain totalmercury contents in acute methyl-mercuric chloride poisoning ratRats were divided randomly into normal control group (Exp1)andexperimental groups ( Exp2-8 ) . Exp2: methyl mercury;Exp3: methylmercury+ L-Cys;Exp4: methyl mercury+ L-Trp;Exp5: methyl mercury+L-Asp;Exp6: methyl mercury+ L-Glu;Exp7: methyl mercury+ L-Lys;Exp8:methyl mercury+ L-Arg.There is 6 rats in every group.The rats in theexperimental groups lavaged by methyl-mercuric chloride in 10mg/kg and last7 days. The rats in the normal control group were given the same volume 0.9%sodium chloride solution. The rats in Exp3-8 were given 15ml/kg variouskinds of amino acids through intraperitoneal injection after 1 hour of havinggiven them methyl mercury, and the rats in the normal control group weregiven the same volume 0.9% sodium chloride solution.In the period ofexperimentation, we will observe symptoms, sings and body weights of acutepoisoning rats.We are going to put them to death in etherization at the tenthday and get their brain tissues.Using atomic absorption method, we willdetermine total mercury contents of brain tissues, organ quotiety, brainhistopathologic changes and amino acids influence on brain mercury contentsdistribution.1) The common symptoms in acute methyl-mercuric chloride poisoningratRats in the trial groups displayed thrix nastiness, fluffiness, piloerection, noaction, gathering, four limbs pedestal capability thinness, bending from thewaist, trail pulling groud and appearing crab-like legs.Some rats appeared hindlimb overlapping and self-cycloversion.The rats in every trial group had thesimilar symptoms, but the ones in the control group lacked them.2)Body weight changes in acute methyl-mercuric chloride poisoning ratRat body weights in every trial group were lessened, but they in the controlgroup were not obvious. It was lower in the group of giving methyl mercuryand cysteine or glutamic acid than methyl mercury only(P<0.05). There wasno difference on rat body weight between the group of giving methyl mercuryand aspartate or lysine or arginine and the group of giving methyl mercuryonly. There was remarkable change on rat body weight comparing in the groupof giving methyl mercury and tryptophane with methyl mercury only, but itwas no statistical significance.3)Organ quotiety in acute methyl-mercuric chloride poisoning ratFigure 3 demostrated that organ quotieties of brain and liver were lower inthe trial group than control group, but the ones of kidney were high. They werelower in the group of giving methyl mercury and cysteine or glutamic acidthan methyl mercury only, but the ones of kidney were higher. There waschange on rat organ quotieties comparing in the group of giving methylmercury and tryptophane with methyl mercury only.but above results are nostatistical significance.There was no difference on rat organ quotieties betweenthe group of giving methyl mercury and aspartate or lysine or arginine and thegroup of giving methyl mercury only.4 ) Brain histopathology changes in acute methyl-mercuric chloridepoisoning ratUsing hematoxylin eosin stain, we observed gliocyte proliferation and gluenodus formation. And cerebellum Purkinje cells desquamated, granule cellsvolume grow downwarded and had karyopycnosis, chromatin dying stronglyand quantity reduction.5 ) Amino acids influence on brain mercury contents in acutemethyl-mercuric chloride poisoning ratBrain mercury contents in the trial group were higher than in the control group(P<0.001).In the groups of giving synchronously different amino acids,brain mercury contents had remarkable changes. It was higher in the group ofgiving methyl mercury and cysteine or glutamic acid than methyl mercuryonly(P<0.001);there was more lower brain mercury contents in the group ofgiving methyl mercury and tryptophane than methyl mercury only(P<0.001);there was no difference between the group of giving methyl mercury andaspartate or lysine or arginine and the group of giving methyl mercury only.In summary, we concluded that it is the amino acids category make a decisionon the effect of amino acids to the brain total mercury content, but there isnothing on acidity or alkality of amino acids.Our study expounded theinfluence of amino acids on brain mercury contents in rat vivo, which willpossess important theory significance on the prevention and cure of methylmercury intoxication...