Objectives: Hyperbaric oxygen (HBO) has been used in the clinical setting to heal problem wounds, yet its direct effects on fibroblasts are not clear. The present study evaluates the effects of HBO on the growth and autocrine production of growth factors by fibroblasts grown in an in vitro, serum-free environment.
Methods: Human dermal fibroblasts were propagated in serum-free media and subjected to daily 90-minute HBO treatments at 1.0, 1.5, 2.0, 2.5, and 3.0 atm of pressure for 7 consecutive days. Cell proliferation and growth-factor assays for basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and transforming growth factor beta1 (TGF-beta1) were performed on days 1, 3, 5, and 7.
Results: On day 1, HBO inhibited growth of fibroblasts at all atmospheric pressures compared with control. By day 7, cell proliferation was significantly enhanced only in cells treated with 2.0-atm HBO compared with controls. Secretion of bFGF was significantly increased by HBO-treated fibroblasts on day 1; VEGF levels slightly increased with HBO treatment on day 1, but this effect was not statistically significant; TGF-beta1 levels were detectable on day 1 only for control and HBO-treated cells at 1.0 atm, and not detectable for any cell groups after day 1.
Conclusions: These results suggest that daily HBO treatment enhances the growth of fibroblasts when administered to a critical degree. Also, HBO appears to directly effect fibroblast production of autocrine growth factors on initial exposure. We postulate that fibroblasts possess the ability to respond to hyperoxia directly, which causes changes in cell signaling pathways involved in cellular proliferation and growth factor production.