Endocrine effects of hexabromocyclododecane (HBCD) in a one-generation reproduction study in Wistar rats.
The brominated flame retardant (BFR) hexabromocyclododecane was tested in a one-generation reproduction assay in Wistar rats, enhanced for endocrine parameters. A solution of the compound in corn oil was mixed in the feed, targeting at dietary exposure of 0-0.1-0.3-1-3-10-30-100 mg/kg body weight/day (mkd) in parental rats during 10 (males) or 2 (females) weeks premating, during gestation and lactation, and in their F1 offspring from weaning until final necropsy. Effects were assessed in F1 animals. Livers of these animals showed increased HBCD concentrations, in a dose-dependent way. The trabecular bone mineral density of the tibia was dose-dependently decreased in females (BenchMark Dose Lower confidence bound, BMDL=0.056 mkd). The IgG response after immunization with sheep red blood cells (SRBC) was increased in males (BMDL=0.46 mkd). Further sensitive effects were decreased weight of the testis (BMDL=1.5 mkd), increased fraction of neutrophilic granulocytes (BMDL=7.7 mkd), decreased concentration of apolar retinoids in female livers (BMDL=1.3 mkd), and decreased plasma alkaline phosphatase in females (BMDL=8.6 mkd). CYP19/aromatase activity in the ovary was correlated to the concentration of gamma-HBCD in the liver. A developmental origin of these effects is considered, and this is also true for sensitive effects observed in neurobehavioural testing in littermates from the same experiment, i.e. in the brainstem auditory evoked potentials and in a catalepsy test [Lilienthal, H., Van der Ven, L.T.M., Piersma, A.H., Vos, J.G. Neurobehavioral effects of the brominated flame retardant hexabromocyclododecane (HBCD) in rats after pre- and postnatal exposure, in press]. The low BMDLs of these effects may raise concern for human health, particularly when based on body burdens of HBCD, which leads to critical margins of exposure particularly for the occupational setting.
van der Ven
Leo T M
LT
Laboratory for Health Protection Research, National Institute of Public Health and the Environment (RIVM), P.O. Box 1, 3720 BA Bilthoven, The Netherlands.
van de Kuil
Ton
T
Leonards
Pim E G
PE
Slob
Wout
W
Lilienthal
Hellmuth
H
Litens
Sabina
S
Herlin
Maria
M
Håkansson
Helen
H
Cantón
Rocío F
RF
van den Berg
Martin
M
Visser
Theo J
TJ
van Loveren
Henk
H
Vos
Josephus G
JG
Piersma
Aldert H
AH
D000818:Animals; D001822:Body Burden; D001835:Body Weight / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects; D052244:Endocrine Disruptors / Q000633:toxicity*; D005260:Female; D005333:Fetus / Q000187:drug effects*; D005411:Flame Retardants / Q000633:toxicity*; D012739:Gonadal Steroid Hormones / Q000502:physiology; D006842:Hydrocarbons, Brominated / Q000633:toxicity*; D007107:Immune System / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009929:Organ Size / Q000187:drug effects; D011247:Pregnancy; D051381:Rats; D012098:Reproduction / Q000187:drug effects*; D012176:Retinoids / Q000378:metabolism; D013094:Spermatozoa / Q000187:drug effects
D052244:Endocrine Disruptors; D005411:Flame Retardants; D012739:Gonadal Steroid Hormones; D006842:Hydrocarbons, Brominated; D012176:Retinoids; C089796:hexabromocyclododecane