Measurement of changes in mouse tail collagen with age: Temperature dependence and procedural details

Abstract

A method for determining the breaking times of mouse tail tendon fibers in 7 M urea is described. These breaking times correlate well with the age of the fiber donor, especially with donors of the same genotype. The procedure does not harm the fiber donor, and may be repeated four times using the same individual. The temperature of the urea solution must be held constant (we used 45·0°C) for reproducible results, but double fibers, the particular tail tendon bundle used, fiber length or dryness, exact urea concentration, and local anesthesia do not affect breaking times. The portion of a tail tendon fiber that is under the body skin increases in breaking time with age more rapidly than the portion of the same fiber that is outside the body in the base of the tail. Furthermore, fibers from the base of the tail very close to the body age more rapidly than fibers in the center of the tail. We suggest that these accelerated aging rates are associated with localized differences in temperatures, because the body temperature is 6°C higher than that of the base of the tail, while the center of the tail is 3°C cooler than the base.