ABSTRACT
Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear hormone receptor family of ligand-inducible transcription factors. Our previous study has shown that in human umbilical vein endothelial cells PPARβ initiates a protective mechanism that limits the extent of damage due to H2O2-induced injury. Although fibroblasts are one of the main cell types involved in wound repair, the role of PPARβ in the fibroblast response to heat injury has not been investigated. Thus, in this study, we examined possible protective role of PPARβ in fibroblasts from heat injury. We developed a novel dermal fibroblast heat injury model to characterize the mechanisms of the heat injury healing response that involved PPARβ. The specific PPARβ ligand GW0742, a PPARβ activator and a short hairpin RNA (shRNA) plasmid against PPARβ were used to reveal the action mechanism of PPARβ in heat injury-induced fibroblast changes in morphology and increased proliferation. In response to heat injury (52˚C for 30 s), fibroblast activation of PPARß, increased 1.56-fold. Administration of GW0742 significantly induced a protective effect on heat injury-induced fibroblasts by minimizing the structural damage and increasing the cell proliferation response. Likewise, inhinition of PPARß, usingh shRNA exacerbated the damage by inhibiting the de novo synthesis of PPARß. These results indicated that heat injury enhanced PPARß expression and PPARß protected fibroblast structure and proliferation.
Subject(s)
Fibroblasts/physiology , Heat Exhaustion/therapy , Heat Stress Disorders/therapy , Heat Stroke/therapy , Humans , PPAR-betaABSTRACT
O prognóstico do colapso pelo calor esforço induzido depende do produto do tempo de duração em que a temperatura central ficou elevada e do grau da elevação. O atleta com EHS que tem pronta descoberta e que é resfriado de maneira eficiente, muito provavelmente irá sobreviver ao episódio com pouco ou nenhum efeito residual. Em contraste, o atleta com apresentação atrasada para o tratamento, especialmente se a área sob a curva de resfriamento for > 60 graus-minuto (centígrados) terá um curso complicado e geralmente fatal. Os métodos de condução do resfriamento com imersão em gelo ou água gelada ou envolvimento em toalhas com água gelada proporcionarão uma rápida e consistente redução da temperatura de todo o corpo, que irá salvar tanto os órgãos quanto a vida. O reconhecimento depende em alto grau da suspeita por parte dos próprios atletas, treinadores e pessoal médico local. Em condições de alto risco, os atletas devem se supervisionar, procurando por mudanças sutis que podem ser sinais de EHS.(AU)The prognosis for exertional heat stroke depends upon the product of length of time the core temperature is elevated and the degree of elevation. The athlete with EHS who is discovered promptly and efficiently cooled will most likely survive the episode with little if any residual. In contrast, the athlete who has delayed presentation for treatment, especially if the area under to cooling curve is > 60 degree-minutes (centigrade), will have a complicated and often fatal course. Conductive cooling methods with ice or cool water immersion or rotating ice water cooled towels provide rapid and consistent whole body temperature reduction that is both organ and life saving. Recognition depends on a high index of suspicion on the part of athletes, coaches, and onsite medical personnel. In high risk conditions, athletes should "buddy up" to watch for subtle changes that can signal the onset of EHS.(AU)El pronóstico del choque térmico (CT) relacionado con el ejercicio depende...