Intervertebral disk mineralization in progressive ankylosis mice.

The objective of this study was to quantitate the increasing mineral content of the intervertebral disk of progressive ankylosis mice and to identify changes in serum and bone mineral levels that might occur concurrent with the rapid mineralization of the disk. Serum calcium (8.43 +/- 1.01 mg/dl vs. 7.48 +/- 2.07) and phosphorus (6.66 +/- 1.32 mg/dl vs. 5.53 +/- 2.19) levels were within normal limits. Ankylosing mice had a 5.2% decrease in water content, a 24% increase in calcium content and a 29% decrease in phosphorus content of the intervertebral disks. The magnitude of these changes increased with age. There was no significant difference in mineral or water content of the vertebral bodies. The mineral levels per gram of tissue were much greater in ankylosing disks than in the vertebral bodies. No correlation was identified between ankylosing disks and serum or bone mineral levels.