Are skeletally mature female rats a suitable model to study osteoporosis?
OBJECTIVE
To analyze if female Wistar rats at 56 weeks of age are a suitable model to study osteoporosis.


METHODS
Female rats with 6 and 36 weeks of age (n = 8 per group) were kept over a 20-week period and fed a diet for mature rodents complete in terms of Ca, phosphorous, and vitamin D. Excised femurs were measured for bone mass using dual-energy x-ray absorptiometry, morphometry, and biomechanical properties. The following serum markers of bone metabolism were analyzed: parathyroid hormone (PTH), osteocalcin (OC), osteoprotegerin (OPG), receptor activator of nuclear factor Κappa B ligand (RANKL), C-terminal peptides of type I collagen (CTX-I), total calcium, and alkaline phosphatase (ALP) activity.


RESULTS
Rats at 56 weeks of age showed important bone metabolism differences when compared with the younger group, such as, highest diaphysis energy to failure, lowest levels of OC, CTX-I, and ALP, and elevated PTH, even with adequate dietary Ca.


CONCLUSIONS
Rats at 26-week-old rats may be too young to study age-related bone loss, whereas the 56-week-old rats may be good models to represent the early stages of age-related changes in bone metabolism.
Food and Nutrition Department, Food and Engineering College, Universidade Estadual de Campinas, SP, Brasil. claucnetto@gmail.com
Claudia Cardoso
CC
Netto
Vivian Cristine Correia
VC
Vieira
Lizanka Paola Figueiredo
LP
Marinheiro
Sherry
S
Agellon
Hope
H
Weiler
Mário Roberto
MR
Maróstica
D015502:Absorptiometry, Photon; D000367:Age Factors; D000375:Aging / Q000502:physiology; D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D015415:Biomarkers / Q000097:blood; D015519:Bone Density; D002118:Calcium / Q000097:blood; D004195:Disease Models, Animal; D005260:Female; D005269:Femur / Q000378:metabolism / Q000503:physiopathology; D010024:Osteoporosis / Q000378:metabolism* / Q000503:physiopathology; D051381:Rats; D053246:Receptor Activator of Nuclear Factor-kappa B / Q000097:blood; D015203:Reproducibility of Results; D013997:Time Factors
D015415:Biomarkers; D053246:Receptor Activator of Nuclear Factor-kappa B; D000469:Alkaline Phosphatase; D002118:Calcium