title: Changes in compact bone microstructure of rats subchronically exposed to cadmium.
abstract: BACKGROUND
  Chronic exposure to cadmium (Cd), even at low concentrations, has an adverse impact on the skeletal system. Histologically, primary and secondary osteons as basic structural elements of compact bone can also be affected by several toxicants leading to changes in bone vascularization and mechanical properties of the bone. The current study was designed to investigate the effect of subchronic peroral exposure to Cd on femoral bone structure including histomorphometry of the osteons in adult male rats. In our study, 20 one-month-old male Wistar rats were randomly divided into two experimental groups. In the first group, young males received a drinking water containing 30 mg of CdCl2/L, for 90 days. Ten one-month-old males without Cd intoxication served as a control group. After 90 days of daily peroral exposure, body weight, femoral weight, femoral length, cortical bone thickness and histological structure of the femora were analysed.
  
  
  RESULTS
  We found that subchronic peroral application of Cd had no significant effect on body weight, femoral length and cortical bone thickness in adult rats. On the other hand, femoral weight was significantly increased (P < 0.05) in Cd-intoxicated rats. These rats also displayed different microstructure in the middle part of the compact bone where vascular canals expanded into central area of substantia compacta and supplied primary and secondary osteons. Additionally, a few resorption lacunae which are connected with an early stage of osteoporosis were identified in these individuals. Histomorphometrical evaluations showed that all variables (area, perimeter, maximum and minimum diameter) of the primary osteons' vascular canals, Haversian canals and secondary osteons were significantly decreased (P < 0.05) in the Cd group rats. This fact points to alterations in bone vascularization.
  
  
  CONCLUSIONS
  Subchronic peroral exposure to Cd significantly influences femoral weight and histological structure of compact bone in adult male rats. It induces an early stage of osteoporosis and causes reduced bone vascularization. Histomorphometrical changes of primary and secondary osteons allow for the conclusion that the bone mechanical properties could be weakened in the Cd group rats. The current study significantly expands the knowledge on damaging action of Cd on the bone.
authors.affiliation: Department of Zoology and Anthropology, Constantine the Philosopher University, 949 74, Nitra, Slovakia. hduranova@ukf.sk.
authors.forename: Hana
authors.initials: H
authors.lastname: Duranova
authors.affiliation: Department of Zoology and Anthropology, Constantine the Philosopher University, 949 74, Nitra, Slovakia. mmartiniakova@ukf.sk.
authors.forename: Monika
authors.initials: M
authors.lastname: Martiniakova
authors.affiliation: Department of Botany and Genetics, Constantine the Philosopher University, 949 74, Nitra, Slovakia. romelka@ukf.sk.
authors.forename: Radoslav
authors.initials: R
authors.lastname: Omelka
authors.affiliation: Institute of Zoology and Anthropology, Georg-August University, 37 073, Göttingen, Germany. birgit.grosskopf@biologie.uni-goettingen.de.
authors.forename: Birgit
authors.initials: B
authors.lastname: Grosskopf
authors.affiliation: Department of Zoology and Anthropology, Constantine the Philosopher University, 949 74, Nitra, Slovakia. ivana.bobonova@gmail.com.
authors.forename: Ivana
authors.initials: I
authors.lastname: Bobonova
authors.affiliation: Department of Veterinary Sciences, Slovak University of Agriculture, 949 76, Nitra, Slovakia. robert.toman@uniag.sk.
authors.forename: Robert
authors.initials: R
authors.lastname: Toman
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects; D019256:Cadmium Chloride / Q000633:toxicity*; D002113:Calcification, Physiologic / Q000187:drug effects; D005269:Femur / Q000187:drug effects*; D008297:Male; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D059550:Toxicity Tests, Subchronic; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D019256:Cadmium Chloride