title: Alterations induced by chronic lead exposure on the cells of circadian pacemaker of developing rats.
abstract: Lead (Pb) exposure alters the temporal organization of several physiological and behavioural processes in which the suprachiasmatic nucleus (SCN) of the hypothalamus plays a fundamental role. In this study, we evaluated the effects of chronic early Pb exposure (CePbe) on the morphology, cellular density and relative optical density (OD) in the cells of the SCN of male rats. Female Wistar rats were exposed during gestation and lactation to a Pb solution containing 320 ppm of Pb acetate through drinking water. After weaning, the pups were maintained with the same drinking water until sacrificed at 90 days of age. Pb levels in the blood, hypothalamus, hippocampus and prefrontal cortex were significantly increased in the experimental group. Chronic early Pb exposure induced a significant increase in the minor and major axes and somatic area of vasoactive intestinal polypeptide (VIP)- and vasopressin (VP)-immunoreactive neurons. The density of VIP-, VP- and glial fibrillary acidic protein (GFAP)-immunoreactive cells showed a significant decrease in the experimental group. OD analysis showed a significant increase in VIP neurons of the experimental group. The results showed that CePbe induced alterations in the cells of the SCN, as evidenced by modifications in soma morphology, cellular density and OD in circadian pacemaker cells. These findings provide a morphological and cellular basis for deficits in circadian rhythms documented in Pb-exposed animals.
authors.affiliation: Subdirección de Medicina Experimental, Instituto Nacional de Pediatría, México DF, México. rocajc1@yahoo.com.mx
authors.forename: Julio César
authors.initials: JC
authors.lastname: Rojas-Castañeda
authors.forename: Rosa María
authors.initials: RM
authors.lastname: Vigueras-Villaseñor
authors.forename: Patricia
authors.initials: P
authors.lastname: Rojas
authors.forename: Margarita
authors.initials: M
authors.lastname: Chávez-Saldaña
authors.forename: Oscar
authors.initials: O
authors.lastname: Gutiérrez-Pérez
authors.forename: Sergio
authors.initials: S
authors.lastname: Montes
authors.forename: Camilo
authors.initials: C
authors.lastname: Ríos
mesh_terms: D000818:Animals; D057906:Circadian Clocks / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006624:Hippocampus / Q000196:embryology / Q000378:metabolism / Q000473:pathology; D007031:Hypothalamus / Q000196:embryology / Q000378:metabolism / Q000473:pathology; D007854:Lead / Q000009:adverse effects* / Q000097:blood / Q000494:pharmacology*; D008297:Male; D023421:Models, Animal; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D017397:Prefrontal Cortex / Q000196:embryology / Q000378:metabolism / Q000473:pathology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D013493:Suprachiasmatic Nucleus / Q000187:drug effects* / Q000196:embryology* / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism; D014667:Vasopressins / Q000378:metabolism
chemical_list: D005904:Glial Fibrillary Acidic Protein; D014667:Vasopressins; D007854:Lead; D014660:Vasoactive Intestinal Peptide