The variation of sonic plesio-velocity in dose dependent lathyritic rabbit femurs.

It has been hypothesized that the origin of the increased elastic modulus of mineralized bone compared with the demineralized bone matrix is in the higher crosslinking density of the collagen in bone. Osteolathyrism is ascribed to an inhibition of crosslinking of the collagen by the lathyrogen and should be accompanied by a decrease in the elastic modulus of the bone. Dose dependent osteolathyrism was induced by varying the amount of BAPN ingested per day by young New Zealand white rabbits until they were mature. The femurs exhibited dose dependent properties, including wet bone density and sonic plesio-velocity in the radial direction. It was found that there is no minimum critical dose. Even though no overt osteolathyritic stigmata could be observed, both the sonic properties and the wet bone density could be affected at any dose level. The sonic plesio-velocity and the longitudinal elastic modulus decreased with BAPN dose level, most rapidly at the lower dose levels and then less so at higher dosages. Since BAPN acts to inhibit the crosslinking density, it appears that the elastic moduli of bone are dependent on the crosslinking density.