The collagenous and non-collagenous protein of the canine intervertebral disc and their variation with age, spinal level and breed.

The total nitrogen, collagen and non-collagenous protein (NCP) content of the nucleus pulposus (NP), transitional zone (TZ) and annulus fibrosus (AF) of the beagle (a chondrodystrophoid breed) and greyhound (a non-chondrodystrophoid breed) intervertebral discs have been determined over the age range birth to 124 months. Discs were sampled at three spinal levels - lumbosacral, lumbar and thoracic regions. The beagle NP attains an average NP collagen content of 25% dry weight before 11 months of age, whereas the greyhound NP content is less than 5% collagen for most of its life. The NCP of the young greyhound disc is greater than that of the beagle of corresponding age. Plots of the ratio of collagen/NCP for discal regions at various ages highlight the large differences between the two breeds of dog. It is suggested that these differences in protein distribution are related to the elevated incidence of intervertebral disc prolapse in the beagle.