Studies Of Mutagenic Teratogenic And Long-term Toxicity Of Bronopol

Objective: The purpose of this study was to determine the potential toxicity,potential target oragen or delayed occurrence potential toxic effects of Bronopol, whenadministered orally by gavage for SD rat in single dose and repeated dose for90days.Mutagenic and teratogenic were also observed, potential exposure dangerous evaluationwas conducted.Methods: one hundred (100) rats (bodyweight range120-150g) were randomlyassigned to4groups of10/sex/group, an additional10species/sex were ordered forrecovery period for control and high dose group. The test article was administered orallyvia gavage once daily for90days, at dose level of0、20、40、and80mg/kg. Mortality,clinical observations, bodyweight, food consumption were evaluated; a completenecropsy was conducted on all surviving animals after dosing period in main study,organs were collected for histopathology evaluation, blood and urine were collected forhematology, serum chemistry, coagulation, urine analysis test. After14days recoveryphase, all the surviving animals in recovery group were euthanized and related physicalexaminations were tested. In Vitro Mammalian Chromosome Aberration Study, CHLcells are exposed to the test substance in S9presence (50、20、10、3mg/L) and in S9absence (30、10、5、2.5mg/L). In Vitro Mammalian Cell Gene Mutation Study, CHOcells were exposed to the test substance with the concentration of20,10,5and2.5mg/L. On Ames study, TA97, TA98, TA100, TA102�'�TA1535bacterial suspensionwere exposed to the test substance in the presence （50、25、12.5、6.25and3.125μg/plate） and absence （30、15、7.5、3.75and1.875μg/plate）of an exogenousmetabolic activation system(S9). Mammalian Erythrocyte Micronucleus Study,60ICRmice were assigned to6groups including three concentrations (20、40、80mg/kg formales；25、50、100mg/kg for females) of Bronopol as well as positive and negativecontrols. Teratogenic study, total of100pregnant animals were randomly assigned to5 groups (20/group), dosage for each group were designed as1.75、17.5、35and70mg/kg.Animals were administrated once every day from gestation Day6to17. Body weightswere measured on GD0,3,7,10,13,16and20. Food consumptions were measuredon GD0-3,3-7,7-10,10-13,13-16, and16-20. On GD21, all the main study animalswere necropsied and examined macroscopically. The ovaries and uteri were examinedfor determination of litter data. All the live fetuses were weighed and examined forexternal abnormalities; their crown-lump length was measured and their sex wasdetermined. Approximately1/2of the live fetuses in each litter were fixed withmodified Davidson’s fixative for soft tissue examination and the remaining fetuses werestained with Alizarin red solution for subsequent skeletal examination.Results:8animals were died from dose related toxicity in90day repeated dosestudy. Toxicity reaction noticed during study were activity descrease, abdominaldistension, body weight lose (especially male), food consumption descrease, WBCreduce (especially males in high group), increase of GLU (especially males in mid andhigh group), tachypnea and blepharoptosis. No target orage was found in histopathologyevaluation; however, the gastrointestinal irritation were noted after necropsy forunscheduled dead animals. In Vitro Mammalian Chromosome Aberration Study, thechromosome aberration rate was less than4.5%, and there was also no significantincrease in chromosome structural aberrations per cell and cells with structuralaberrations for all test concentrations groups. In Vitro Mammalian Cell Gene MutationStudy, There was no significant difference in mutation frequency for all test groups incontrast with that of the negative control. On Ames study, the number of revertantcolonies in the test strains was not increased more than two-fold regardless ofapplication of metabolic activation system as compared with that of the negative controlgroup. Mammalian Erythrocyte Micronucleus Study, there was no significant increasein appearance rate of micronucleated polychromatic erythrocytes in polychromaticerythrocytes for all treatment groups in contrast with that of a negative control.Teratogenic study, dose related toxicity reaction were observaed, including activitydescrease, tachypnea and blepharoptosis. Clinical observations in high dose group werenoted more than mid group, there were no test article related changes in litterparameter, body weight, gross lesion, live fetuses, fetal weight, fetal length, fetal sexratio, and fetal structure (external and visceral). The high dose group has significantly higher incidences of incomplete ossifications than control while the mid dose level hasno significant fetal effects, This is extremely true when looking into the two litters inthe high dose group which have the highest incidence of skeletal alterations,。Conclusion:90day oral repeated dose to rat by Bronopol, LOAEL is40mg/kg/dayand the NOAEL is20mg/kg/day. No target organs were found. Bronopol is negative inBacterial Reverse Mutation Assay (Ames), In Vitro Mammalian ChromosomeAberration Test (CHL), In Vitro Mammalian Cell Gene Mutation Test (CHO) andMammalian Erythrocyte Micronucleus Test. Bronopol had no obviously teratogenicityto rat, the NOAEL values for maternal effects and fetus should be35mg/kg/d.