Bone Abstracts

Aim: Investigate strength features of humerus in rats with defects in tibiae after 60-day per os administration of sodium benzoate (SB).

Materials and methods: The experiment involved 210 rats with initial body weight of 200–210 g. The animals were separated into six groups as follows: Group 1 comprised animals that received per os 1 ml of 0.9% solution of sodium chloride daily (C), Group 2 (D) comprised animals with plain defects of 2.2 mm of diameter in proximal part of the shaft; Groups 3 and 4 received daily SB in dosage of 500 or 1000 mg/kg of body weight (B1 and B2) and Groups 5 and 6 comprised the animals with the same defects in tibiae as those of Group D that received SB in the same way as Groups B1 and B2 (B1D and B2D). After termination of observation terms the humeri were taken for bending strength test.

Results: Obtained show that SB and fracture (a defect in tibia) have negative effects on bone strength of humerus as far as breaking point values in the Groups B1D and B2D were lower than those of the Group D by 6.20 and 6.84% respectively and breaking moment values were lower than values of the same Group D by 7.59 and 7.14% respectively. In readaptation period strength restored markedly slower than in other groups: by the 24th day after SB discontinue breaking point values in the Groups B1D and B2D were lower than those of the Group D by 6.98 and 9.81% respectively. Also by the same time showed breaking moment and facture energy lower than those of the Group D by 7.21 and 6.32%. By the 45th day in both B1D and B2D Groups the same values were not significantly different than those of Group D.

Conclusions: Defect in tibia after 60-day administration of SB result in slower restore of bone strength. SB in dosage of 100 mg/kg of body weight had more pronounced effects on bone strength. Significant changes were found up to the 24th day of observation and group B2D exhibited more marked deviations than other groups.