title: Effects of drug treatment on bone strength and structural changes with aging: an experimental study in rats.
abstract: The purpose of the present study was to evaluate the profiles of the bone strength of rats treated from infancy with various drugs. Young female Sprague-Dawley rats were classified into five groups according to the composition of their diets. They underwent resection of their femurs for a three-point flexion test and an impaction test at 6, 8, 12, and 16 months of age. A microcomputed tomography unit was used to evaluate the microstructure of their femoral condyles at 16 months of age. The diet given to the rats in the control group contained 0.5% Ca. The rats in groups A, B, C, and D were placed on the following regimens, respectively: vitamin K mixed diet, vitamin D oral administration, 1.8% Ca-fortified diet, and 1.8% Ca-fortified diet plus vitamin K and vitamin D. In the impaction tests conducted on the rats at each age, the results from groups A and B were nearly the same as those from the control group. At 16 months of age, the rats in groups C and D had significantly higher test results than those in the control group. In the three-point flexion tests at 16 months of age, the results from groups A, B, and C were nearly the same as those from the control group. The results from group D, however, showed a significant increase. Examination of the microstructure of the femoral condyles at 16 months of age revealed controlled destruction of the trabecular structure in groups C and D. These findings suggest that supplementing the diet from infancy with Ca, vitamin K, and vitamin D might prevent bone fractures due to osteoporosis.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013718:Tensile Strength / Q000187:drug effects; D014057:Tomography, X-Ray Computed / Q000379:methods; D014807:Vitamin D / Q000494:pharmacology*; D014812:Vitamin K / Q000494:pharmacology*
chemical_list: D014812:Vitamin K; D014807:Vitamin D; D002118:Calcium