Impact of Thermo-Responsive N-Acetylcysteine Hydrogel on Dermal Wound Healing and Oral Ulcer Regeneration.

This study investigates the efficacy of a thermo-responsive N-acetylcysteine (NAC) hydrogel on wound healing and oral ulcer recovery. Formulated by combining NAC with methylcellulose, the hydrogel's properties were assessed for temperature-induced gelation and cell viability using human fibroblast cells. In vivo experiments on Sprague Dawley rats compared the hydrogel's effects against saline, NAC solution, and a commercial NAC product. Results show that a 5% NAC and 1% methylcellulose solution exhibited optimal outcomes. While modest improvements in wound healing were observed, significant enhancements were noted in oral ulcer recovery, with histological analyses indicating fully regenerated mucosal tissue. The study concludes that modifying viscosity enhances NAC retention, facilitating tissue regeneration. These findings support previous research on the beneficial effects of antioxidant application on damaged tissues, suggesting the potential of NAC hydrogels in improving wound care and oral ulcer treatment.

Oral ulcer treatment using human tonsil-derived mesenchymal stem cells encapsulated in trimethyl chitosan hydrogel: an animal model study.

BACKGROUND: Oral ulcers are a common side effect of chemotherapy and affect patients' quality of life. While stem cell transplantation is a potential treatment for oral ulcers, its efficacy is limited as the stem cells tend to remain in the affected area for a short time. This study aims to develop a treatment for oral ulcers by using trimethyl chitosan (TMC) hydrogel with human tonsil-derived stem cells (hTMSCs) to increase the therapeutic effect of stem cells and investigate their effectiveness. METHODS: Animals were divided into four experimental groups: Control, TMC hydrogel, hTMSCs, and hTMSCs loaded in TMC hydrogel (Hydrogel + hTMSCs) (each n = 8). Oral ulcers were chemically induced by anesthetizing the rats followed by injection of dilute acetic acid in the right buccal mucosa. After confirming the presence of oral ulcers in the animals, a single subcutaneous injection of 100 µL of each treatment was applied to the ulcer area. Histological analyses were performed to measure inflammatory cells, oral mucosal thickness, and fibrosis levels. The expression level of inflammatory cytokines was also measured using RT-PCR to gauge therapeutic the effect. RESULTS: The ulcer size was significantly reduced in the TMC hydrogel + hTMSCs group compared to the control group. The stem cells in the tissue were only observed until Day 3 in the hTMSCs treated group, while the injected stem cells in the TMC Hydrogel + hTMSCs group were still present until day 7. Cytokine analysis related to the inflammatory response in the tissue confirmed that the TMC Hydrogel + hTMSCs treated group demonstrated superior wound healing compared to other experimental groups. CONCLUSION: This study has shown that the adhesion and viability of current stem cell therapies can be resolved by utilizing a hydrogel prepared with TMC and combining it with hTMSCs. The combined treatment can promote rapid healing of oral cavity wounds by enhancing anti-inflammatory effects and expediting wound healing. Therefore, hTMSC loaded in TMC hydrogel was the most effective wound-healing approach among all four treatment groups prolonging stem cell survival. However, further research is necessary to minimize the initial inflammatory response of biomaterials and assess the safety and long-term effects for potential clinical applications.

Photobiomodulation Recovers the Submandibular Gland in Vismodegib-Treated Rats.

Objective: The submandibular gland (SMG) produces the most saliva, and factors such as aging and chemotherapy can affect its structure and function. However, there are only temporary treatments available for salivary hypofunction. This study aimed to evaluate the effects of photobiomodulation (PBM) on the function of SMG by using a rat animal model and vismodegib, an antagonist of the sonic hedgehog (SHH) pathway. Methods: Vismodegib (10 mg/kg) drug was gavaged orally for 14 days in rats to significantly decrease the SHH signaling proteins [SHH, protein patched homolog 1 (PTCH1), smoothened protein (SMO), glioma-associated oncogene homolog 1 (GLI1)], induce damage in SMG tissue, and affect salivary functional markers AQP5 and Keratin5. After that, in conjunction with vismodegib administration, PBM was performed using an 850 nm high-power light-emitting diode (LED) device treated daily for 6 days at varying total energy densities of 60, 120, and 180 J/cm2 in at least 3 rats per group. The test results were confirmed by Western blot, immunofluorescence staining, and hematoxylin and eosin staining, and the statistics were t-test or one-way analysis of variance (ANOVA) with Tukey's multiple comparisons tests. Results: Significant decreases in the expression of SHH-related proteins (PTCH1, SMO, GLI1, p < 0.05) with damage of SMG ductal cells were observed with vismodegib administration. However, a significant increase in the expression levels of SHH-related proteins (SHH, SMO, GLI1, p < 0.05) and recovery of SMG ductal cells damaged after vismodegib administration were observed for PBM-treated groups. Salivary functional marker AQP5 also showed the same increase or decrease. Conclusions: This study found that vismodegib damages SMG ductal cells and decreases SHH-related proteins and associated salivary functional markers. Also, 850 nm high-power LED recovered the damaged structure of SMG and increased SHH-related proteins and salivary functional markers. The study results suggest that PBM can restore SMG structure and function through SHH signaling.

Photobiomodulation enhances M2 macrophage polarization properties of tonsil-derived mesenchymal stem cells.

In this study, the effect of photobiomodulation (PBM) treatment using 630 nm light emitting diode (LED) array (continuous wave type, 10 mW power) on tonsil-derived mesenchymal stem cells (TMSCs) and its interaction with RAW 264.7 macrophage cells via co-culture in vitro were investigated. PBM treatment was used as a priming method for TMSCs to improve therapeutic efficacy. TMSCs were subjected to multi-dose PBM treatments before co-culture with M1 activated (1 µg/mL lipopolysaccharide, LPS) macrophage cells with total energy doses of 0, 15, 30, and 60 J. Irradiation set at 15 J (1500 s treatment time) was performed once, twice for 30 J, and four times for 60 J in an incubator kept at 37 °C and 5% CO2. No significant anti-inflammatory response was observed for TMSCs co-cultured with macrophage cells without PBM. But PBM treatment of TMSCs with 630 nm LED array at 30 J reduced expression of inducible nitric oxide synthase, iNOS (M1) and increased expression of Arginase-1, Arg-1 (M2) phenotype macrophage markers. Anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1RA) gene expression also increased significantly. Based on the results, PBM priming of TMSCs supports M2 macrophage polarization. PBM can be used to improve the therapeutic efficacy of TMSCs for potential applications in oral mucositis and wound healing.

Trimethyl chitosan postoperative irrigation solution modulates inflammatory cytokines related to adhesion formation.

Lavage or irrigation has been instilled in surgical practice for wound clearance and surgical site infection prevention during and after surgery. Herein, we developed a new irrigation solution using trimethyl chitosan (TMC), a quaternized chitosan derivative. The TMC-saline irrigation solution developed in the study possesses highly effective bactericidal properties with hemostatic and anti-adhesion properties. The anti-adhesion property of TMC was investigated in relation to inflammatory cytokine response and wound healing. TMC-saline irrigation solution showed reduced pro-inflammatory cytokine protein and gene expressions relevant in the cascade of wound healing and cytokine-related orchestration of postoperative adhesion formation. Further development of this multifunctional TMC-saline irrigation solution can be beneficial for surgical applications and postoperative wound management.

Improved healing and macrophage polarization in oral ulcers treated with photobiomodulation (PBM).

OBJECTIVES: The effect of photobiomodulation (PBM) treatment on wound healing and macrophage polarization was investigated in vivo. Animal models of oral ulcers were simulated through chemically induced oral ulcers in rats. MATERIALS AND METHODS: PBM treatment using an infrared pulsed laser was used to treat oral ulcers in the animal models. Twelve Sprague-Dawley rats were randomly divided into four groups depending on set absorbed energy: Group 1 (control), Group 2 (30 J), Group 3 (60 J), and Group 4 (100 J). Laser treatment was performed every other day for 8 days after ulcer confirmation. Parameters used were as follows: wavelength 808 nm, power output 50 mW, spot size 10 mm, frequency 10 Hz, and pulse duration 1 millisecond. Ulcers were measured to determine the effect of the treatments over time. Histology, immunostaining, and real-time polymerase chain reaction analyses were performed to evaluate the effect of PBM treatment on macrophage-related (IL-6/IL-10) and wound-healing-related (TNF-α/TGF-ß/MMP-2) cytokine expression. RESULTS: Histological examinations indicate that the PBM treatment stimulated a higher level of wound recovery after 8 days of treatment at 60 J absorbed energy compared to other treatment groups. Analyses of relative gene expression of proinflammatory, anti-inflammatory, and tissue remodeling cytokines indicate that the macrophages in the tissue samples were predominantly characterized as M2 subtypes (alternatively activated), which possibly accounts for the accelerated tissue repair in the animal model of oral ulcer. CONCLUSION: This preliminary study stands as a proof of concept regarding the potential use of infrared laser PBM treatment for oral ulcers which have not been previously investigated upon. PBM treatment affects macrophage polarization and enhances wound healing. Further experimentation will be conducted to expand the understanding of how PBM treatment affects the healing mechanism of ulcers.

Evaluation of egg white ovomucin-based porous scaffold as an implantable biomaterial for tissue engineering.

Studies have shown the technological and functional properties of ovomucin (OVN) in the food-agricultural industry. But research has yet to explore its potential as an implantable biomaterial for tissue engineering and regenerative medicine. In this study we isolated OVN from egg white by isoelectric precipitation and fabricated scaffolds with tunable porosity by utilizing its foaming property. Gelatin a known biocompatible material was introduced to stabilize the foams, wherein different ratios of OVN and gelatin had a significant effect on the degree of porosity, pore size and stability of the formed hydrogels. The porous scaffolds were crosslinked with EDC resulting in stable scaffolds with prolonged degradation. Improved cell proliferation and adhesion of rat bone marrow-derived mesenchymal stem cells were observed for OVN containing scaffolds. Although, scaffolds with 75% OVN showed decrease in cell proliferation for L929 fibroblast type of cells. Further biocompatibility assessment as implant material was determined by subcutaneous implantation in rats of selected scaffold. H&E staining showed reasonable vascularization over time and little evidence of severe fibrosis at the implant site. Persistent polarization of classically activated macrophage was not observed, potentially reducing inflammatory response, and showed increased expression of alternatively activated macrophage cells that is favorable for tissue repair. Analysis of IgE levels in rat serum after implantation indicated minimal and resolvable allergic response to the OVN implants. The results demonstrate OVN as an acceptable implant scaffold that could provide new opportunities as an alternative natural biocompatible and functional biomaterial in various biomedical applications. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2107-2117, 2017.