VEGF Expression of Cultured Keloid Fibroblasts from Different Donor Sites Under Normoxic and Hypoxic Conditions

Moon, Hyung Sik; Son, Sook Ja; Park, Kun; Kang, Hee Gyoo; Lim, Hee Joung; Park, Hyang Jun

Abstract

BACKGROUND: The pathophysiological events resulting in keloid formation remain unclear. Overabundant levels of VEGF have been reported to contribute to excessive wound healing. There have been many studies describing the relationship between keloids and VEGF expression. However, there have been no reports about VEGF expression related to donor sites.
OBJECTIVE
We investigated VEGF expression of cultured normal and keloid fibroblasts obtained from different body areas under normoxic and hypoxic culture conditions.
METHODS
Normal fibroblasts from the earlobe (n=2), shoulder (n=2) and chest (n=2) as well as keloid fibroblasts from the earlobe (n=3), shoulder (n=3) and chest (n=3) were collected and cultured. VEGF expression of fibroblasts at 6 hours, 12 hours, 24 hours and 48 hours for cells maintained under normoxic and hypoxic conditions was measured by the use of RT-PCR. Paraffin-embedded tissues (normal and keloid tissue) were assayed by immunohistochemical staining.
RESULTS
For the cultured normal fibroblasts, VEGF expression for cells in the hypoxic condition was higher as compared to VEGF expression in cells in the normoxic condition, irrespective of the donor site and time. However, for the cultured keloid fibroblasts, VEGF expression for cells in the hypoxic condition was higher as compared to VEGF expression in cells in the normoxic condition for cultured shoulder fibroblasts. For each donor site, VEGF expression was highest in the shoulder, followed by the chest and earlobe for cultured normal fibroblasts, irrespective of time. For the cultured keloid fibroblasts, the highest VEGF expression occurred at 6 hours for cells in the normoxic condition and the highest VEGF expression occurred at 6 hours and 12 hours for cells in the hypoxic condition. Based on immunohistochemical staining, VEGF expression of paraffin-embedded normal tissue was lower as compared to paraffin-embedded keloid tissue. For each donor site in paraffin-embedded keloid tissue, VEGF expression was highest in the shoulder, followed by the chest and earlobe.
CONCLUSION
Oxygen tension and the nature of fibroblasts from different donor sites are involved in keloid pathogenesis.