Effect of Mechanical Stretching of the Skin on Collagen Fibril Thermal Stability

Stabilization of collagen fibres during development and through growth to maturation has now become fairly documented. In vitro effect of mechanical stretching of ratsf skin on oxidative deamination of ε-NH2-groups of lysine and hydroxylysine, and functional properties of its type . collagen were studied. Experiments were carried out on the skin of a 3-months old male Wistar rat weighing about 800 mg. The skin tissue was divided into four (4) and subjected to different mechanical stresses in Ringer-Krebfs medium for 6 hours at 37 oC. The Degree of oxidative deamination of lysine and hydroxylysine was evaluated by way of the content of free ε-amino (ε-NH2) and aldehyde (COH) groups. Level of covalent cross-linking of collagen in skin samples was assessed by its solubility in 1 M solution of NaCl and expressed as a percentage of total collagen content in the tissue. Collagen synthesized under the influence of mechanical stretching had higher content of free ε-NH2-groups and lower level of inter-molecular cross-links compared to the collagen synthesized without the stretching. This finding may indicate that fibrils formed in the former were shorter and had lower thermal stability due to a decrease in the degree of cross linkages.Keywords: Connective tissue, collagen, cross-linkage, fibril, mechanical stretching, oxidative deamination, thermal stability