ISOTONIC AND ISOMETRIC THERMAL CONTRACTION OF HUMAN DERMIS .2. AGE-RELATED CHANGES

[摘要] The shrinkage temperature, amount of contraction, and rate and amount of tension developed during isotonic and isometric hydrothermal contraction of dermal collagen were determined on samples of normal skin taken from 124 individuals ranging in age from 32 weeks of gestation to 88 years. Measurement of total tension corrected for dermal thickness was found to be the most sensitive indicator of collagen change. This increased rapidly from 26 gm at 32 weeks of gestation to 60 to 70 gm by age 2 years. This was followed by a leveling off with a slight dip at puberty and then a slow steady rise beginning in the late twenties or early thirties to 100 to 120 gm by old age. Both the shrinkage temperature and the amount of contraction showed a small nonspecific increase with age. The findings suggest that normal collagen becomes increasingly stable with age and that this increase may result from both a maturation and a degenerative process, acting at different rates on the collagen molecules. The dip at puberty is most likely a reflection of the high hormonal levels known to occur during this period.