Navegando por Autor "Segismondi, Larissa Cavallieri"

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    Efeito sinérgico da fotobiomodulação com LED 660 E 850 nm em células L929 induzidas ao estresse oxidativo com peróxido de hidrogênio
    (2025-09-09) Soares, Luís Eduardo Silva; Arisawa, Emília Angela Loschiavo; Oliveira, Luciane Dias de; Segismondi, Larissa Cavallieri; Soares, Cristina Pacheco; São José dos Campos
    A pele está constantemente exposta a agressões externas, tornando-se um alvo para a geração excessiva de espécies reativas de oxigênio (ROS), que induzem danos oxidativos principalmente na região dérmica. A fotobiomodulação (FBM) mostra-se uma terapia eficiente para biomodulação de sistemas biológicos, capaz de modular processos oxidativos e inflamatórios. No presente estudo, buscou-se elucidar o possível efeito fotoprotetor in vitro da aplicação simultânea da FBM com LED 660 e 850 nm em células fibroblásticas L929 diante do tratamento com peróxido de hidrogênio como modelo de estresse oxidativo. Os fibroblastos foram pré-irradiados com LED e em seguida incubados com 200 µM de H2O2 diluído em meio de cultura pelo período de 3 horas. Após 24 horas dos tratamentos, foram observadas alterações quanto à atividade mitocondrial pelo ensaio colorimétrico Alamar Blue e quanto à morfologia celular por microscopia invertida. Também foi realizada a marcação de mitocôndrias e núcleos em células vivas por fluorescência utilizando Tetrametilrodamina (TMRM) e Tricloridrato de bisbenzimida (HOESCHT), além da detecção de ROS por fluorescência utilizando CellRox Orange. Os resultados obtidos indicam que o pré-tratamento com LED promove aumento da atividade mitocondrial, do potencial da membrana mitocondrial, redução da geração de ROS intracelular e induz alterações morfológicas nas células. Dessa maneira, conclui-se que o sinergismo entre os LEDs 660 e 850 nm exerce efeito protetor contra a ação do H2O2 em células fibroblásticas L929, demonstrando que a FBM pode ser utilizada para auxiliar a prevenir e mitigar danos oxidativos.
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    In vitro evaluation of red and near infrared LED photobiomodulation on L929 fibroblasts metabolic activity and morphology
    (Springer) Segismondi, Larissa Cavallieri; Soares, Luís Eduardo Silva; Pacheco-Soares, Cristina
    Purpose Fibroblasts, the main cells of connective tissue, are highly susceptible to oxidative stress caused by reactive oxygen species (ROS). Photobiomodulation (PBM) has emerged as a promising therapy capable of modulating biological tissues, enhancing cellular metabolic activity, and promoting the proliferation and survival of fibroblasts. In this study, we aimed to investigate the potential in vitro photoprotective effect of cellular photomodulation using 660 and 850 nm LEDs in L929 fibroblast cells treated with hydrogen peroxide as a model of oxidative stress. Methods Changes in cell viability were observed using the Alamar Blue colorimetric assay, and cell morphology was assessed by inverted microscopy. Mitochondria and nuclei were also labeled in living cells using fluorescence with TMRM and Hoechst, in addition to ROS detection with CellRox Green. Results Our results indicate that pretreatment with LED exerts a cytoprotective effect against oxidative stress, promoting an increase in mitochondrial activity, mitochondrial membrane potential, and a reduction in intracellular reactive oxygen species (ROS) generation while inducing improvements in the morphological characteristics of cells. Conclusion The findings from the present study indicate that Photobiomodulation (PBM) with LED contributes to maintaining cellular homeostasis and can help prevent and mitigate damage resulting from oxidative stress in fibroblasts.
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    In vitro evaluation of red and near infrared LED photobiomodulation on L929 fibroblasts metabolic activity and morphology
    (Springer) Segismondi, Larissa Cavallieri; Soares, Luís Eduardo Silva; Soares, Cristina Pacheco
    Purpose Fibroblasts, the main cells of connective tissue, are highly susceptible to oxidative stress caused by reactive oxygen species (ROS). Photobiomodulation (PBM) has emerged as a promising therapy capable of modulating biological tissues, enhancing cellular metabolic activity, and promoting the proliferation and survival of fibroblasts. In this study, we aimed to investigate the potential in vitro photoprotective effect of cellular photomodulation using 660 and 850 nm LEDs in L929 fibroblast cells treated with hydrogen peroxide as a model of oxidative stress. Methods Changes in cell viability were observed using the Alamar Blue colorimetric assay, and cell morphology was assessed by inverted microscopy. Mitochondria and nuclei were also labeled in living cells using fluorescence with TMRM and Hoechst, in addition to ROS detection with CellRox Green. Results Our results indicate that pretreatment with LED exerts a cytoprotective effect against oxidative stress, promoting an increase in mitochondrial activity, mitochondrial membrane potential, and a reduction in intracellular reactive oxygen spe- cies (ROS) generation while inducing improvements in the morphological characteristics of cells. Conclusion The findings from the present study indicate that Photobiomodulation (PBM) with LED contributes to maintain- ing cellular homeostasis and can help prevent and mitigate damage resulting from oxidative stress in fibroblasts.