Scanning Electron Microscopic Study of Age Related Changes in the Collagen Fiber Architecture of Rat Palatal Mucosa

Abstract

We investigated age related changes in the arrangement of the collagen fiber network of palatal mucosa using female Sprague-Dawley strain rats between 3 and 90 weeks of age. A cell-maceration/scanning electron microscope method was employed to demonstrate the three-dimensional architecture of the collagen fibers.
At low magnification, the connective tissue papillae on the rugae become enlarged and more complex in shape with age until ten weeks, but become less complex after 32 weeks. At high magnification, exposed collagen fiber networks of the connective tissue surface were observed in all specimens. Numerous microridges made up of interwoven collagen fibers were observed on the connective tissue surface, and two types of microridges were found : large wall-like and small bundle-like microridges.
Differences in the number and shape of microridges by location were observed at the same age. The microridges increased in number and extended towards the epidermis with age until 10 weeks, and the shape of the microridges became more complex until 32 weeks. At 90 weeks, the microridges decreased in number and size. The collagen fiber network on the connective tissue surface became tighter with age until 32 weeks, but it loosened at 90 weeks.
These results indicate that rat palatal mucosa have different collagen fiber architectures by location, and their structures change with age.