Degeneration of the intervertebral disks and spondylosis in aging sand rats.

Aging sand rats (Psammomys obesus) kept on a standard laboratory diet supplemented by salt bush--their natural source of food--were examined for changes of the vertebral column. From about 6 months of age on, degeneration of the intervertebral disks was noted. The changes increased in severity with increasing age, and from 1 1/2 years of age on, massive multiple disk herniations were seen. Associated with these lesions were spondylosis of "intervertebral" as well as hyperostotic type, and osteoarthrosis of the apophyseal joint. The sand rat seems to be an excellent model for the study of the pathogenesis of spinal diseases associated with the aging process.