ISSN: 2640-2637
Authors: Alcantara Quintana Luz Eugenia*, Garcia Ruiz Gilberto F, Teran Figueroa Yolanda, Rodriguez Fuentes Nayeli, Benitez Arvizu Gamaliel
Introduction: Post-burn hypertrophic scar tissue (Hsc) is characterized by increased collagen synthesis, cellular growth (hyperplasia) and cell turnover (shedding). Its clinical characteristics (erythema, pain, dysesthesia, pruritus, elevation) exhibit aspects of chronic local inflammation, but the mechanism of its etiopathogenesis has not been clearly elucidated. In chronic skin inflammation, pro inflammatory and profibrogenic cytokines play an important role in producing skin dysfunction. In this study, we examined changes in tumor necrosis factor (TNF)-α and interleukin (IL)-1 β mRNA expression and its presence in post-burn hypertrophic scars in stem cells. Results obtained in normotrophic scar tissue (Nsc) were compared to results obtained in normal skin (Ns). Materials and Methods: Skin biopsies were obtained from 15 patients with (Hsc) who presented burns on over 10% of their skin surface, more than a year post-injury. Nsc was obtained from 17 patients who experienced scarring in optimal conditions. Ns were obtained from 11 patients who underwent cosmetic or reconstructive surgery. We performed histopathology analysis with routine processing. TNF-α and IL-1β mRNA expression levels on all three types of biopsy were obtained via semi-quantitative RT-PCR, RT-qPCR, western blot and by in situ hybridization. Results: When analyzing mRNA expression levels by semi-quantitative RT-PCR, and qPCR we observed higher TNF-α and IL-1β levels in post-burn hypertrophic scar tissue relative to normal skin and normotrophic scar tissue. In contrast, in situ hybridization revealed significant differences in IL-1β hybridization intensity localized in Hsc epidermis relative to Nsc and Ns epidermis. For TNF-α, expression intensity in epidermis and dermis did not differ between Ns, Nsc and Hsc. Wefound higher TNF-α-positive porcentage of cells in the epidermis of Ns and Hsc relative to Nsc; meanwhile IL-1β-positive percentage of cells were higher in the epidermis of Hsc as compared to Ns and Nsc. Our histopathologic analysis yielded relatively low inflammatory infiltrate cell counts, and we found no correlation between inflammatory infiltrate cell count and cytokines produced. Conclusion: Together these results suggest that there is increase in TNF-α and IL-1β mRNA expression in post-burn Hsc. Interestingly, the basal keratinocytes (stem cells) showed differential expression of both cytokines compared to other cell types, which suggests that they may play an important role in post-burn skin repair processes.
Keywords: Burns; Inflammation; Collagen; Keratinocytes; Proinflammatory Cytokines
