Bone Abstracts

In this study, the effect of food restriction of 30% in calorie intake on femurs of rats of different ages was investigated. Male Rattus novegicus albinus rats, Holtzman lineage, aged 38 days, 4 and 16 months were used. The animals were divided into six groups (n=8–10 per group), three being control groups (C38, C4 and C16) and three groups on restricted diet (R38, R4 on R16). The restricted animals were submitted to food restriction of 30% being fed with 70% of the ad libitium consumption of the control group. Protocol Ethics Committee on Animal Experimentation n° 057/2012. Analysis of the biometric, biophysical, biomechanical and biochemical properties of bone tissue were performed. Animals on restricted diet had a shorter femur length (R38=33.39±0.73; R4=39.04±0.90) in comparison with their controls (C38=35.79±0.72; C4=40.23±0.89), but no difference was observed between 16 months groups (C16=42.15±0.94; R16=42.08±0.95). The restriction diet reduced the thickness of the femur in the group aged 38 days (C38=5.34±0.41; R38=4.62±0.18) but not in restricted to groups 4 (C4=6.04±0.15; R4=5.90±0.27) and 16 months (C16=5.81±0.48; R16=6.06±0.29). Animals aged 38 days in food restriction also presented reduction of bone volume (C38=0.59±0.03; R38=0.47±0.03). This effect was not observed in group 4 (C4=0.72±0.03; R4=0.70±0.05) and 16 months (C16=0.73±0.40; R=16 0.74±0.04). The femoral calcium content reduced in restricted diet rats with 38 days (C38=134.50±9.48; R38=88.45±8.04) and 4 months (C4=197.10±15.97; R4=152,00±12.05), but no difference was observed for group 16 months (C16=170.90±20.73; R16=164.60±14.27). No differences in the biomechanical properties resulting from food restriction were observed (maximum load; maximum load until fracture; displacement until fracture; stiffness and tenacity). The diet food restriction resulted in harm to bone development with remarkable loss in prepubertal rats, inconsistent alterations in young adult rats and potential benefits to bones of elderly rats.