Microenvironmental Control of Monokine Production in Wound Repair.

The macrophage is an important regulatory cell in host defense and wound healing. The ability of the macrophage to respond to varipus microenvironmental stimuli may be an important regulatory mechanism. Using a constant perifusion tissue culture system and human peripheral blood monocytes, we rigidly controlled oxygen environments, pH and CO2. Hypoxic and normoxic oxygen environments 2 and 20 were tested with and without gamma interferon. The collected, concentrated supernatants were then tested for PDGF, TGFB, TNF, IL-1 alpha and beta, IL-6, and angiogenesis activity. Hypoxia increased production of angiogenesis. Levels of TGFB and nitrous oxides were present and similar in both oxygen environments, while PDGF and IL-1 were not detected. The level of IL-6 was decreased in hypoxia and the combination of hypoxia and IFN drives IL-6 production to zero. Further experimentation on culture conditions showed that there was continued macrophage death during the perifusion and scanning electron micrographs showed that the plating density was lower than anticipated. These experiments are the first attempt to our knowledge to use constant perifusion of macrophages to model the microenvironments these cells are exposed to in vitro.