Interleukin-31, Interleukin-31RA, and OSMR Expression Levels in Post-burn Hypertrophic Scars

BACKGROUND: Although several studies have shown the role of interleukin-31 (IL-31) and its receptors in inducing pruritus in certain skin disorders, knowledge of its role in post-burn hypertrophic scars is insufficient. Therefore, the histopathological expression levels of IL-31, IL-31 receptor alpha (IL-31RA), and oncostatin M receptor (OSMR) in post-burn hypertrophic scar tissues were investigated and compared with normal tissue expression levels. METHODS: Samples of hypertrophic scar tissue were obtained from 20 burn patients through punch biopsy. Normal samples were obtained from areas adjacent to the burn injury site of the same patients. Samples were placed in 10% neutral buffered formalin, embedded in paraplast, and processed into serial 5-μm sections. Immunohistochemistry results were semi-quantitatively evaluated for IL-31, IL-31RA, and OSMR. By hematoxylin and eosin staining, epidermal and dermal thickness were assessed with a microscope and digital camera. Intensities were rated on a scale of 1 to 4. RESULTS: Percentages for IL-31, IL-31RA, and OSMR in the epidermal basal layer cell cytoplasm were significantly greater in the burn scar tissue compared to normal skin, as well as the dermal and epidermal thickness (p < .05). There was a significant difference in IL-31 epidermal basal layer intensity in burn scar tissue compared to normal skin (p < .05). Besides the OSMR basal layer intensity, IL-31 and IL-31RA intensities between the burn scar and normal tissues were not significant. However, correlations were significant, indicating that the greater the infiltration percentage, the higher the intensity (p < .05). CONCLUSIONS: IL-31, IL-31RA, and OSMR expression levels are increased in hypertrophic scars compared with normal tissue.