Wound splinting modulates wound cell proliferation

Abstract

Introduction: Rigid anchorage of the extracellular matrix is important for fibroblast survival and proliferation in vitro. We hypothesized that rigid matrix anchorage in a wound splinting model would modulate wound cell proliferation in vivo.Methods: Male rats (age = 3 months; N = 12) were excisionally wounded (4 cm2 square of dermis + panniculus from the dorsum), and a square stainless steel splint was sutured to the wound edge. The splint was removed on day 5 from 6 rats. The animals were injected with BrdU 18 hr later, and then the granulation tissue with surrounding dermis was excised 24 hr after desplinting. BrdU- and propidium iodide-labeled nuclei were quantified on frozen sections of granulation tissue, cut at three different levels. Results: A total of 201 microscopic sections were counted (about 16 per rat), representing about 37,000 nuclei. The rate of BrdU-positive nuclei in the splinted vs. desplinted animals was 6.15 ± sd 2.45 vs. 3.03 ± 1.58%∗, and the total number of nuclei per microscopic field was 175 ± 27 vs. 197± 38∗, respectively (∗p < 0.001, unpaired t-test). Wound cross-sectional area decreased approximately 50% after desplinting (data not shown). Conclusions: Removal of the rigid wound splint decreased the rate of BrdU-labeled cells in the granulation tissue by 50%; there was a slight increase in the cell population density, which may be explained by the contraction which occurs after desplinting. Wound cell proliferation is modulated by anchorage of the wound edge.