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dc.contributor.authorMelin, Vanessa Estellaen_US
dc.date.accessioned2017-01-16T07:00:11Z
dc.date.available2017-01-16T07:00:11Z
dc.date.issued2015-07-25en_US
dc.identifier.othervt_gsexam:5598en_US
dc.identifier.urihttp://hdl.handle.net/10919/74337
dc.description.abstractQuaternary ammonium compounds (QACs) are antimicrobial disinfectants commonly used in commercial and household settings. While these compounds have been used for decades, reproductive toxicity has not been thoroughly evaluated. Extensive use of QACs results in ubiquitous human exposure to potentially toxic compounds. Reproductive toxicity of two common QACs, alkyl dimethyl benzyl ammonium chloride (ADBAC) and didecyl dimethyl ammonium chloride (DDAC), was investigated to determine gender-specific toxicity with an emphasis on male reproductive function. Breeding pairs of mice exposed for six months to ADBAC+DDAC exhibited decreases in fertility and fecundity, with fewer pregnancies and decreased numbers of pups over a six month period. Females proceeded through significantly fewer estrus cycles, and both ovulation and implantation rates were reduced. Males exhibited declines in both sperm concentration and motility. Male reproductive toxicity was further assessed in a series of in-vitro and in-vivo experiments. ADBAC+DDAC were cytotoxic to testicular Sertoli cells in culture at concentrations greater than or equal to 0.0005%. Changes in blood-testis-barrier integrity (BTB) were observed at 0.01% ADBAC+DDAC using a two-compartment culture system that measures transepithelial electrical resistance (TER). Sertoli cell cytotoxicity correlated with decreased TER at ADBAC+DDAC concentrations above 0.001%. In-vitro fertilization capacity of epididymal sperm was reduced in males given a 10-day rest period following ADBAC+DDAC exposure. Multigenerational changes in sperm parameters and in mRNA expression of enzymes involved with epigenetic modifications were evaluated across three generations. Sperm concentration and motility were reduced in F0 males exposed directly to ADBAC+DDAC. In F1 males, sperm concentration was increased and motility decreased, while there was no change in the F2 progeny. Genes involved in epigenetic modifications were altered in the exposed F0, with upregulation of two histone acetyltransferases (Hat1 and Kat2b) and downregulation of one lysine-specific demethylase (Kdm6b). F1 and F2 generations were not different from controls except for downregulation of the methyltransferase Dnmt1 in F1 progeny. The reproductive toxicity of ADBAC+DDAC identified in these studies, particularly to the male, compels further investigation into the potential effects that these compounds may have on human reproduction.en_US
dc.format.mediumETDen_US
dc.publisherVirginia Techen_US
dc.rightsThis Item is protected by copyright and/or related rights. Some uses of this Item may be deemed fair and permitted by law even without permission from the rights holder(s), or the rights holder(s) may have licensed the work for use under certain conditions. For other uses you need to obtain permission from the rights holder(s).en_US
dc.subjectquaternary ammonium disinfectantsen_US
dc.subjectinfertilityen_US
dc.subjectreproductive toxicologyen_US
dc.subjecttestisen_US
dc.subjectspermatogenesisen_US
dc.subjectepigeneticsen_US
dc.titleEFFECTS OF QUATERNARY AMMONIUM DISINFECTANTS ON MOUSE REPRODUCTIVE FUNCTIONen_US
dc.typeDissertationen_US
dc.contributor.departmentVeterinary Medicineen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineBiomedical and Veterinary Sciencesen_US
dc.contributor.committeechairEhrich, Marion F.en_US
dc.contributor.committeechairHrubec, Theresaen_US
dc.contributor.committeememberPrater, Mary R.en_US
dc.contributor.committeememberMagnin-Bissel, Geraldine C.en_US
dc.contributor.committeememberHuckle, William Ruperten_US


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