Wound cell variation in closed surgical wounds as measured with two independent methods.

Background and aims: It is not known, to what extent the observed cellular changes in healing surgical wounds are species-, individual- or site-specific or whether they depend on the research method used. The aim of this study was to compare two independent methods for harvesting wound cells from porcine wounds after two time intervals, and to assess individual changes of wound cell composition.

Material and methods: In a standardised wound model in six pigs, with eight dorsal skin incision wounds in each, the Cellstick device and the Wound Edge Contact (WEC) method were used to collect inflammatory cells from the same wounds at hour 6 or 24 post-surgery. The wound cells were stained by the May-Grünwald-Giemsa (MGG) -method and counted differentially.

Results: A significant difference was found between the 6 and 24 hour Cellstick specimen in the proportions of wound neutrophils (p = 0.007), lymphocytes (p = 0.02) and monocytes (p < 0.001). The differential counts of wound cells within each individual animal did not significantly differ from each other. Instead, a significant difference was found in the wound neutrophils (p = 0.001), lymphocytes (p = 0.04) and monocytes (p < 0.001) between the wounds of individual animals. The WEC method revealed the same significant differences in the wound cell proportions.

Conclusions: The Cellstick and the WEC method gave analogous results with equal variances from the incision wounds for up to at least 24 hours after injury.