Alterations induced by chronic lead exposure on the cells of circadian pacemaker of developing rats

• Published in: International journal of experimental pathology 2011-08, Vol.92 (4), p.243-250
• Main Authors: Rojas-Castañeda, Julio César, Vigueras-Villaseñor, Rosa María, Rojas, Patricia, Chávez-Saldaña, Margarita, Pérez, Oscar Gutiérrez, Montes, Sergio, Ríos, Camilo
• Format: Article
• Language: English
• Subjects: Acetic acid; Age; Animals; Blood; Circadian Clocks - drug effects; Circadian rhythms; Cortex (prefrontal); Dose-Response Relationship, Drug; Drinking water; Female; Gestation; Glial fibrillary acidic protein; Glial Fibrillary Acidic Protein - metabolism; Hippocampus; Hippocampus - embryology; Hippocampus - metabolism; Hippocampus - pathology; Hypothalamus - embryology; Hypothalamus - metabolism; Hypothalamus - pathology; Lactation; Lead; Lead - adverse effects; Lead - blood; Lead - pharmacology; Male; Models, Animal; Neurons; Neurons - drug effects; Neurons - metabolism; Neurons - pathology; Optical density; Original; Pacemakers; Prefrontal Cortex - embryology; Prefrontal Cortex - metabolism; Prefrontal Cortex - pathology; Pregnancy; Prenatal Exposure Delayed Effects - metabolism; Prenatal Exposure Delayed Effects - pathology; Rats; Rats, Wistar; relative optical density; Suprachiasmatic nucleus; Suprachiasmatic Nucleus - drug effects; Suprachiasmatic Nucleus - embryology; Suprachiasmatic Nucleus - metabolism; Vasoactive intestinal peptide; Vasoactive Intestinal Peptide - metabolism; vasoactive intestinal polypeptide; Vasopressin; Vasopressins - metabolism; Weaning
• ISSN: 0959-9673; 1365-2613
• DOI: 10.1111/j.1365-2613.2011.00761.x

Summary 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.