title: Chronic lead poisoning magnifies bone detrimental effects in an ovariectomized rat model of postmenopausal osteoporosis.
abstract: Lead (Pb) is a persistent environmental contaminant that is mainly stored in bones being an important source of endogenous lead exposure during periods of increased bone resorption as occurs in menopause. As no evidence exists of which bone biomechanical properties are impaired in those elderly women who had been exposed to Pb during their lifetime, the aim of the present study is to discern whether chronic lead poisoning magnifies the deterioration of bone biology that occurs in later stages of life. We investigated the effect of Pb in the femora of ovariectomized (OVX) female Wistar rats who had been intoxicated with 1000 ppm of Pb acetate in drinking water for 8 months. Structural properties were determined using a three-point bending mechanical test, and geometrical and material properties were evaluated after obtaining the load/deformation curve. Areal Bone Mineral Density (BMD) was estimated using a bone densitometer. Femoral histomorphometry was carried out on slices dyed with H&E (Hematoxylin and Eosin). Pb and OVX decreased all structural properties with a higher effect when both treatments were applied together. Medullar and cortical area of femurs under OVX increased, allowing the bone to accommodate its architecture, which was not observed under Pb intoxication. Pb and OVX significantly decreased BMD, showing lead treated ovariectomized rats (PbOVX) animals the lowest BMD levels. Trabecular bone volume per total volume (BV/TV%) was decreased in OVX and PbOVX animals in 54% compared to the control animals (p<0.001). Pb femurs also showed 28% less trabeculae than the control (p<0.05). We demonstrated that Pb intoxication magnifies the impairment in bone biomechanics of OVX rats with a consequent enhancement of the risk of fracture. These results enable the discussion of the detrimental effects of lead intoxication in bone biology in elderly women.
authors.affiliation: Department of Physiology, Faculty of Dentistry, University of Buenos Aires, Argentina.
authors.forename: Ching Ming
authors.initials: CM
authors.lastname: Lee
authors.affiliation: Department of Physiology, Faculty of Dentistry, University of Buenos Aires, Argentina.
authors.forename: Antonela Romina
authors.initials: AR
authors.lastname: Terrizzi
authors.affiliation: Department of Physiology, Faculty of Dentistry, University of Buenos Aires, Argentina.
authors.forename: Clarisa
authors.initials: C
authors.lastname: Bozzini
authors.affiliation: Department of Toxicology and Legal Chemistry, Faculty of Pharmacy and Biochemistry, University of Buenos Aires, Argentina.
authors.forename: Adriana Emilce
authors.initials: AE
authors.lastname: Piñeiro
authors.affiliation: Department of Physiology, Faculty of Dentistry, University of Buenos Aires, Argentina.
authors.forename: María Inés
authors.initials: MI
authors.lastname: Conti
authors.affiliation: Department of Physiology, Faculty of Dentistry, University of Buenos Aires, Argentina. Electronic address: fliapico@hotmail.com.
authors.forename: María Pilar
authors.initials: MP
authors.lastname: Martínez
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000187:drug effects / Q000473:pathology* / Q000503:physiopathology*; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D007855:Lead Poisoning / Q000150:complications*; D009942:Organometallic Compounds / Q000633:toxicity*; D015663:Osteoporosis, Postmenopausal / Q000150:complications*; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar
chemical_list: D009942:Organometallic Compounds; C008261:lead acetate
keywords: Bone biomechanics; Lead poisoning; Ovariectomy