All about wrinkles - Expression lines and fibroblastic contractions

When we furrow our brows, or make some other kind of expression, the repeated pulling or traction exerted on the skin by subcutaneous facial muscles creates tension in the very place where expression fines form, This tension affects the dermal, or inner, layer of the skip by way of the collagen fibres upon which fibroblasts are anchored.

Fibroblasts are cells that produce such skin components as collagen and elastin. They are made up of a cytoskeleton, a kind of mini-cellular muscle system with contractile power. The alternating contraction and relaxation of fibroblasts is a dynamic process that is influenced by various chemical signals and a number of physical stresses. Dermal micro-tensions caused by muscle contractions modify the contractile properties of the fibroblasts located beneath the line or wrinkle, which results in their becoming "hypercontractile," that is, abnormally subject to contraction or tension. This fibroblastic "hypercontractibility" is absent or minor in the fibroblasts present in those dermal areas that are not exposed to the forces of traction.