DIFFERENTIAL TNF SECRETION BY WOUND FIBROBLASTS COMPARED TO NORMAL FIBROBLASTS IN RESPONSE TO LPS

Fibroblasts cultured from wound sites have been shown to have an alter ed phenotype compared to normal dermal fibroblasts and are generally r egarded as target cells of the cytokine response at sites of injury. T his study was undertaken to determine whether wound fibroblasts can co ntribute to proinflammatory cytokine production in wounds and, in part icular, whether they are capable of secreting TNF. Wound fibroblasts w ere cultured from polyvinyl alcohol sponges implanted subcutaneously f or 2 weeks in Balb/c mice. Fibroblasts harvested from the skin and sub cutaneous tissue of untreated mice served as a control population of c ells. All cells were passaged at least twice and then stimulated with a dose range of LPS. Supernatants were harvested 8 hr following stimul ation and TNF was assayed using a standard L929 cell-killing assay. Th ere was a significant TNF response to LPS by wound fibroblasts, eviden t as early as 4 hr following exposure to LPS and associated with an up regulation of TNF mRNA. Normal dermal fibroblasts did not secrete any measurable amounts of TNF in response to LPS. The results indicate tha t wound fibroblasts generate a brisk TNF response to stimulation with LPS, in contrast to normal subcutaneous fibroblasts. These data reveal an additional unique property of wound-harvested fibroblasts and sugg est a possible contributing mechanism to disordered wound healing in t he face of infection or conditions characterized by excessive fibrosis . (C) 1995 Academic Press, Inc.