Effects of hyperbaric oxygen therapy on rat facial skin

Introduction: We used immunohistochemistry to investigate the histopathologic effects of hyperbaric oxygen (HBO) on the facial skin of rats. Material and methods: Rats in the HBO group (n = 6) were placed in a 20 L HBO chamber at 2.5 atmospheres absolute at 25-26 degrees C with 100% oxygen for 90 min/day for 7 days. Following euthanasia, sections of facial skin were removed for examination. Results: Epidermal hyperplasia and degeneration, basal-cell hypertrophy, subepithelial fibrosis, and increased connective tissue were observed in the HBO group. E-cadherin expression was reduced in the epidermis, hair follicles, and sebaceous glands in HBO-treated rats relative to control animals. HBO treatment was associated with vimentin immunoreactivity in fibroblasts, endothelial cells, and the bulbus pilorum of a subset of hair follicles. It also resulted in increased type IV collagen expression within the connective tissue in the hair follicles and sebaceous glands. Conclusion: The HBO group demonstrated epidermal hyperplasia and degeneration, basal-cell hypertrophy, and subepithelial fibrosis. In addition, HBO decreased E-cadherin expression, which suggests that HBO may impair intracellular adhesion. Expression of vimentin and type IV collagen was also observed in the dermis. Increased connective tissue, hemorrhage, and mononuclear cell infiltration were observed in the dermis of HBO-treated animals. Thus, HBO has effects on the structures of the epidermis and dermis.