The plasticizer butyl benzyl phthalate induces genomic changes in rat mammary gland after neonatal/prepubertal exposure.
BACKGROUND
Phthalate esters like n-butyl benzyl phthalate (BBP) are widely used plasticizers. BBP has shown endocrine-disrupting properties, thus having a potential effect on hormone-sensitive tissues. The aim of this study is to determine the effect of neonatal/prepubertal exposure (post-natal days 2-20) to BBP on maturation parameters and on the morphology, proliferative index and genomic signature of the rat mammary gland at different ages of development (21, 35, 50 and 100 days).


RESULTS
Here we show that exposure to BBP increased the uterine weight/body weight ratio at 21 days and decreased the body weight at time of vaginal opening. BBP did not induce significant changes on the morphology of the mammary gland, but increased proliferative index in terminal end buds at 35 days and in lobules 1 at several ages. Moreover, BBP had an effect on the genomic profile of the mammary gland mainly at the end of the exposure (21 days), becoming less prominent thereafter. By this age a significant number of genes related to proliferation and differentiation, communication and signal transduction were up-regulated in the glands of the exposed animals.


CONCLUSIONS
These results suggest that BBP has an effect in the gene expression profile of the mammary gland.
Moral
Raquel
R
Breast Cancer Research Laboratory, Fox Chase Cancer Center, Philadelphia, PA 19111, USA. Raquel.Moral@uab.es
Wang
Richard
R
Russo
Irma H
IH
Mailo
Daniel A
DA
Lamartiniere
Coral A
CA
Russo
Jose
J
D000818:Animals; D000831:Animals, Newborn; D049109:Cell Proliferation / Q000187:drug effects; D005260:Female; D020869:Gene Expression Profiling; D016678:Genome / Q000235:genetics*; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010795:Phthalic Acids / Q000633:toxicity*; D010968:Plasticizers / Q000633:toxicity*; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012741:Sexual Maturation / Q000502:physiology*
D010795:Phthalic Acids; D010968:Plasticizers; C027561:butylbenzyl phthalate