The fetal wound healing matrix is exceptionally rich in hyaluronic aci
d (HA). Fetal wounds heal without scarring or contraction. Noting thes
e observations, we cultured adult dermal explants in the presence of v
arious concentrations of medical-grade HA in vitro. In the presence of
HA, fibroblasts migrated from the dermal explant and multiplied more
rapidly than control explants. Subsequently, sterile toothpicks were u
sed to disrupt (wound) fibroblast monolayers mechanically and the rate
of closure was monitored. Cells cultivated in the presence of 5 mg/ml
of exogenous HA changed in morphology and closed the wound more quick
ly than control cultures. Cells surrounding the wound extended numerou
s podalic processes and showed increased interdigitation. The effect o
f HA on cell proliferation is usually discussed in terms of the mechan
ical effects HA exerts on cells and the extracellular matrix. The phys
iological effect of HA may lie in its ability to act as an accessory r
eceptor in cooperative ligand-binding pathways. For example, HA may bi
nd growth and/or other factors, and thereby increase the effective con
centration of these factors at the cell surface.