Free fatty acids and dialyzed serum alterations of fibroblast populated collagen lattice contraction

Abstract

Fibroblast populated collagen lattices (FPCL) have facilitated the in vitro study of wound contraction and scar contracture. Mixing fibroblasts, serum containing culture medium and soluble collagen, together and then incubating the mixture at 37 °C produces a FPCL. The fibroblasts elongate and spread within the collagen matrix, and by forces associated with cell locomotion they reorganize the collagen fibers. The reorganization of the collagen produces a reduction in size of the FPCL, called lattice contraction. It was also found that dialyzed fetal bovine serum did not support lattice contraction. Supplementing dialyzed serum with fatty acids accelerated lattice contraction. The fatty acid composition of the fibroblast plasma membrane influences that membrane fluidity. These studies demonstrated that lattice contraction was enhanced by the additions of saturated fatty acids in the order of laurate (C-12), palmitic (C-16), and stereate (C-18). With unsaturated fatty acids additions, the order of enhanced lattice contraction was archidonate (4 C = C), linoleate (2 C = C) and oleate (1 C = C). The addition of dialyzed serum with or without fatty acids neither altered ATP-induced cell contraction activity nor cell proliferation. It was concluded that free fatty acid additions do not modulate FPCL contraction by enhancing microfilaments contraction or increasing cell numbers. The mechanism of action was proposed to be by altering cell membrane fluidity. This finding further supports the theory that the mechanism for lattice contraction is cell locomotion, rather than cell contraction.