title: The effects of early lead exposure on the brains of adult rhesus monkeys: a volumetric MRI study.
abstract: Little is known about direct effects of exposure to lead on central nervous system development. We conducted volumetric MRI studies in three groups of 17-year-old rhesus monkeys: (1) a group exposed to lead throughout gestation (n = 3), (2) a group exposed to lead through breast milk from birth to weaning (n = 4), and (3) a group not exposed to lead (n = 8). All fifteen monkeys were treated essentially identically since birth with the exception of lead exposure. The three-dimensional MRI images were segmented on a computer workstation using pre-tested manual and semi-automated algorithms to generate brain volumes for white matter, gray matter, cerebrospinal fluid, and component brain structures. The three groups differed significantly in the adjusted (for total brain size) volumes of the right cerebral white matter and the lateral ventricles. A significant reduction was noted in right cerebral white matter in prenatally exposed monkeys as compared to controls (p = 0.045). A similar reduction was detected in the white matter of the contralateral hemisphere; however, this difference did not achieve statistical significance (p = 0.143). Prenatally exposed monkeys also had larger right (p = 0.027) and left (p = 0.040) lateral ventricles. Depending on the timing of exposure during development, lead may exhibit differential effects with resultant life-long alterations in brain architecture.
authors.affiliation: Center for Clinical Research and Evidence Based Medicine, The University of Texas-Houston Medical School, 6431 Fannin Street, MSB 2.104, Houston, Texas 77030, USA. Robert.E.Lasky@uth.tmc.edu
authors.forename: Robert E
authors.initials: RE
authors.lastname: Lasky
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Luck
authors.forename: Nehal A
authors.initials: NA
authors.lastname: Parikh
authors.forename: Nellie K
authors.initials: NK
authors.lastname: Laughlin
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000473:pathology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007855:Lead Poisoning / Q000473:pathology*; D008253:Macaca mulatta; D008279:Magnetic Resonance Imaging; D015203:Reproducibility of Results; D012727:Sex Characteristics