Simultaneous irradiation of 660 and 808 nm on gingival epithelial cells and fibroblasts induces different patterns of oxidative/antioxidative activities: What is the role of the cell type and irradiation parameters?

The aim of this study was to investigate whether simultaneous irradiation at 660 and 808 nm generates different patterns of oxidative/antioxidative activities compared to consecutive irradiation. Primary cultures of gingival keratinocytes and fibroblasts were exposed to a diose laser (660 ± 2 nm and 808 ± 2 nm, 100 mW, 0.09 cm2 spot area) using double irradiation with the two wavelengths (consecutive or simultaneous) for 6, 10, and 20 s. The two irradiation regimens did not increase cell viability in any of the experimental conditions. Lipid peroxidation was increased after consecutive irradiation in epithelial cells, which was not detected after simultaneous irradiation. After 20s of the simultaneous mode, ROS levels increased, but antioxidative balance decreased. In the fibroblasts, the two double irradiations induced ROS reduction, increase in lipid peroxidation, and improvement of antioxidative balance, mainly after the 20 s irradiation time. In conclusion, simultaneous and consecutive irradiation induced distinct oxidative stress modulation in oral epithelial cells and fibroblasts. The imbalance in the oxidative system observed after longer exposures, allied with the absence of a significant increase in the viability of the two cell types, suggests a contraindication for longer simultaneous irradiation in clinical situations that demand cellular stimulation.

Solitary fibrous tumor of the tongue.

Solitary fibrous tumor (SFT) is a benign mesenchymal neoplasm originally described in pleura with a rare presentation in the oral cavity. Herein, we report a case of a 28-year-old male patient who presented an asymptomatic slow-growing mass in the anterior part of the tongue. Intraoral examination revealed a well-circumscribed mass covered by normal mucosa with a fibrous consistency. Due to non-specific clinical findings, the initial diagnostic hypotheses include benign submucosal neoplasms such as leiomyoma, neurofibroma, SFT, and others. An excisional biopsy was performed. Microscopically, the tumor was surrounded by a thick fibrous capsule; hypo and hypercellular areas were arranged in a storiform pattern with a stroma formed by collagen and abundant vascularization. Tumor cells showed immunopositivity for CD34 and STAT-6 and no expression of CD99, AML, S-100, and Ki-67. According to these findings, the diagnosis of SFT was established. After 24 months, the patient is asymptomatic and has no evidence of recurrence. Although oral involvement is rare, SFT should be included in the differential diagnosis of oral submucosal lesions.

Effect of chronic ethanol ingestion on dendritic cell population during oral mucosal repair: An experimental study.

The aim of this study was to analyze the effect of chronic ethanol ingestion on dendritic cell repopulation during the repair process of rat oral mucosa and in the rat spleen by analyzing the immunohistochemical expression of dendritic cell markers. Wistar rats ingested 20% ethanol solution for 28 days; a surgical wound was performed on the rat tongue after this period. The repair process and the number of CD1a+, CD11c+, and CD207+ cells in the regions adjacent to the wound were determined at day 1, 3, and 7 following the wound as well as in the rat spleen. The wound-only group (no ethanol exposure) had complete reepithelization after 7 days, but this did not occur in the ethanol + wound group at this time point. The inflammatory infiltrate was significantly reduced in animals exposed to ethanol, which also showed significantly lower counts of CD1a+, CD11c+, and CD207+ cells than the wound-only group at all experimental time points. In addition, ethanol exposure also resulted in lower densities of CD11c+ and CD207+ cells in the rat spleen. In conclusion, chronic ethanol intake had a negative impact on dendritic cell numbers, a fact that may contribute to delay in oral mucosa repair.

Photobiomodulation Therapy Minimizes the DNA Damage in 5FU-Treated Gingival Fibroblasts.

5-Fluoroufacil (5FU) is a chemotherapeutic agent indicated for solid tumors but causes oral mucositis, which can be prevented and treated using photobiomodulation therapy (PBMT). It is unknown whether PBMT modifies DNA damage induced by 5FU in oral cells. The aim of this study was to investigate the effect of PBMT on DNA damage and repair and on oxidative stress in gingival fibroblasts exposed to 5FU. Primary gingival fibroblasts were exposed to 5FU and then treated with a laser (660 nm, 100 mW, 1 W cm-2 , 0.09 cm2 spot area) for three different irradiation times (6, 10 or 20 s). Six-second irradiation decreased DNA damage and lipidic peroxidation. All irradiated groups showed low H2AX levels and increased p53 expression. Ten-second irradiation showed a trend to induce high lipidic peroxidation levels and DNA damage than other irradiation groups. In conclusion, the PBMT effect on DNA damage and repair was dependent on the time irradiation: 6 s-time irradiation (6.6 J cm-2 ) protect gingival fibroblasts from 5FU-related genotoxicity and oxidative stress, whereas 10s- and 20s-time irradiations (11.1 J cm-2 and 22.2 J cm-2 , respectively) increased the risk of DNA damage after the 5FU exposure.