Tonsil-derived stem cells as a new source of adult stem cells

Paracrine Factors Released from Tonsil-Derived Mesenchymal Stem Cells Inhibit Proliferation of Hematological Cancer Cells Under Hyperthermia in Co-culture Model

Mesenchymal stem cells (MSCs) are promising biological therapeutic candidates in cancer treatment. As a source of MSCs, palatine tonsil tissue is one of the secondary lymphoid organs that form an essential part of the immune system, and the relation between the secondary lymphoid organs and cancer progression leads us to investigate the effect of tonsil-derived MSCs (T-MSC) on cancer treatment. We aimed to determine the anti-tumoral effects of T-MSCs cultured at the febrile temperature (40 °C) on hematological cancer cell lines. The co-culture of cancer cells with T-MSCs was carried out under fever and normal culture conditions, and then the cell viability was determined by cell counting. In addition, apoptosis rate and cell cycle arrest were determined by flow cytometry. We confirmed the apoptotic effect of T-MSC co-culture at the transcriptional level by using real-time polymerase chain reaction (RT-PCR). We found that co-culture of cancer cells with T-MSCs significantly decreased the viable cell number under the febrile and normal culture conditions. Besides, the T-MSC co-culture induced apoptosis on K562 and MOLT-4 cells and induced the cell cycle arrest at the G2/M phase on MOLT-4 cells. The apoptotic effect of T-MSC co-culture under febrile stimulation was confirmed at the transcriptional level. Our study has highlighted the anti-tumoral effect of the cellular interaction between the T-MSCs and human hematological cancer cells during in vitro co-culture under hyperthermia.

Parathyroid-on-a-chip simulating parathyroid hormone secretion in response to calcium concentration

The parathyroid gland is an endocrine organ that plays a crucial role in regulating calcium levels in blood serum through the secretion of parathyroid hormone (PTH). Hypoparathyroidism is a chronic disease that can occur due to parathyroid defects, but due to the difficulty of creating animal models of this disease or obtaining human normal parathyroid cells, the evaluation of parathyroid functionality for drug development is limited. Although parathyroid-like cells that secrete PTH have recently been reported, their functionality may be overestimated using traditional culture methods that lack in vivo similarities, particularly vascularization. To overcome these limitations, we obtained parathyroid organoids from tonsil-derived mesenchymal stem cells (TMSCs) and fabricated a parathyroid-on-a-chip, capable of simulating PTH secretion based on calcium concentration. This chip exhibited differences in PTH secretion according to calcium concentration and secreted PTH within the range of normal serum levels. In addition, branches of organoids, which are difficult to observe in animal models, were observed in this chip. This could serve as a guideline for successful engraftment in implantation therapies in the future.

Immunomodulatory Effects of Primed Tonsil-Derived Mesenchymal Stem Cells on Atopic Dermatitis via B Cell Regulation

Mesenchymal stem cells (MSCs) ameliorate T-and B cell-mediated immune responses. In particular, tonsil-MSCs (T-MSCs) are attractive candidates for practical and clinical applications because of their ease of acquisition and relatively low immunogenicity compared with other MSC sources. The use of MSCs as a therapeutic tool in atopic dermatitis (AD) has been investigated, but that of T-MSCs remains to be explored. Therefore, we investigated the immunomodulatory effects of primed T-MSCs in AD pathogenesis. In our animal study, primed T-MSCs showed greater immunological suppressive effects than naïve T-MSCs. Additionally, in vitro, the proliferation of B cells was downregulated by the addition of primed T-MSCs compared with naïve T-MSCs. The activation of B cells to differentiate into antibody-secreting cells and produce IgE was also reduced when primed T-MSCs were added. Moreover, under CD40-knockdown conditions, we found that CD40 in primed T-MSCs played a critical role as a regulator of B cell activation and was mediated by the non-canonical NF-κB pathway. Therefore, our findings suggest a promising role for primed T-MSCs in the treatment of AD by regulating B cell-mediated inflammatory responses, which are dependent on CD40 expression on primed T-MSCs mediated through the non-canonical NF-κB pathway.

Delineation of the healthy rabbit tonsil by immunohistochemistry - A short communication

Situated in the oral cavity, the rabbit palatine tonsils are part of the mucosal immune system and help to defend the body against foreign pathogens. Expressed as two oval protrusions in the wall of the oropharynx, the rabbit palatine tonsils are characterized by excretory ducts and trabeculae. We here compare paraffin embedded and cryosections of the healthy rabbit tonsils. This analysis centers on evaluating the differential outcomes resulting from the application of these fixation methodologies in conjunction with immunohistochemical assays targeting collagen I, collagen III, fibronectin, α-smooth muscle actin (α-SMA), and ki67. Subsequent recommendations are provided based on our findings. Furthermore, we demonstrate the advantage of an antigen retrieval step in immunohistochemical labeling of paraffin sections. Basic classical histological stainings as HE, GT and elastin were also performed. Comparison of different stainings and labelings was furthermore performed in serial sections, showing that adjacent to the excretory ducts, the tonsillar tissue was particularly composed of collagen I and fibronectin, while the vessel walls were predominantly α-SMA positive. Moreover, PAR-2 immunohistochemical staining was performed, where a small fraction of the cells found in the tonsillar connective tissue were PAR-2 positive (probably a subpopulation of mast cells), as well as the lumen of some excretory ducts and trabeculae. Collagen III on the other hand was only weakly expressed in the tonsils. Proliferating ki67 positive cells were rare. This endeavor serves to furnish the scientific community with reference imagery pertinent to researchers opting for the rabbit palatine tonsil model. The diversity of staining techniques employed herein establishes a foundational repository of images, primed for comparative analysis against pathological conditions. Furthermore, these images hold the potential to illustrate inter-species variations. For instance, they can be juxtaposed against murine or rodent tonsils, or even offer insights into the human context.

Therapeutic Extracellular Vesicles from Tonsil-Derived Mesenchymal Stem Cells for the Treatment of Retinal Degenerative Disease

BACKGROUND

Retinal degenerative disease (RDD), one of the most common causes of blindness, is predominantly caused by the gradual death of retinal pigment epithelial cells (RPEs) and photoreceptors due to various causes. Cell-based therapies, such as stem cell implantation, have been developed for the treatment of RDD, but potential risks, including teratogenicity and immune reactions, have hampered their clinical application. Stem cell-derived extracellular vesicles (EVs) have recently emerged as a cell-free alternative therapeutic strategy; however, additional invasiveness and low yield of the stem cell extraction process is problematic.

METHODS

To overcome these limitations, we developed therapeutic EVs for the treatment of RDD which were extracted from tonsil-derived mesenchymal stem cells obtained from human tonsil tissue discarded as medical waste following tonsillectomy (T-MSC EVs). To verify the biocompatibility and cytoprotective effect of T-MSC EVs, we measured cell viability by co-culture with human RPE without or with toxic all-trans-retinal. To elucidate the cytoprotective mechanism of T-MSC EVs, we performed transcriptome sequencing using RNA extracted from RPEs. The in vivo protective effect of T-MSC EVs was evaluated using Pde6b gene knockout rats as an animal model of retinitis pigmentosa.

RESULTS

T-MSC EVs showed high biocompatibility and the human pigment epithelial cells were significantly protected in the presence of T-MSC EVs from the toxic effect of all-trans-retinal. In addition, T-MSC EVs showed a dose-dependent cell death-delaying effect in real-time quantification of cell death. Transcriptome sequencing analysis revealed that the efficient ability of T-MSC EVs to regulate intracellular oxidative stress may be one of the reasons explaining their excellent cytoprotective effect. Additionally, intravitreally injected T-MSC EVs had an inhibitory effect on the destruction of the outer nuclear layer in the Pde6b gene knockout rat.

CONCLUSIONS

Together, the results of this study indicate the preventive and therapeutic effects of T-MSC EVs during the initiation and development of retinal degeneration, which may be a beneficial alternative for the treatment of RDD.

Conditioned medium from human tonsil-derived mesenchymal stem cells inhibits glucocorticoid-induced adipocyte differentiation

Obesity, which has become a major global health problem, involves a constitutive increase in adipocyte differentiation signaling. Previous studies show that mesenchymal stem cells (MSCs) induce weight loss and glycemic control. However, the mechanisms by which MSCs regulate adipocyte differentiation are not yet known. In this study, we investigated the effects of conditioned medium obtained from human tonsil-derived MSCs (T-MSC CM) on adipocyte differentiation. We found that T-MSC CM attenuated adipocyte differentiation from early stages via inhibiting glucocorticoid signaling. T-MSC CM also increased the phosphorylation of p38 mitogen-activated protein kinase and glucocorticoid receptors and decreased the subsequent nucleus translocation of glucocorticoid receptors. Chronic treatment of mice with synthetic glucocorticoids induced visceral and bone marrow adipose tissue expansion, but these effects were not observed in mice injected with T-MSC CM. Furthermore, T-MSC CM injection protected against reductions in blood platelet counts induced by chronic glucocorticoid treatment, and enhanced megakaryocyte differentiation was also observed. Collectively, these results demonstrate that T-MSC CM exerts inhibitory effects on adipocyte differentiation by regulating glucocorticoid signal transduction. These findings suggest that the therapeutic application of T-MSC CM could reduce obesity by preventing adipose tissue expansion.

Development of Surgically Transplantable Parathyroid Hormone-Releasing Microbeads

Hypoparathyroidism is an endocrine disorder that occurs because of the inability to produce parathyroid hormone (PTH) effectively. Previously, we reported the efficacy of tonsil-derived mesenchymal stem cells (TMSCs) differentiated into parathyroid-like cells for the treatment of hypoparathyroidism. Here, we investigated the feasibility of three-dimensional structural microbeads fabricated with TMSCs and alginate, a natural biodegradable polymer, to treat hypoparathyroidism. Alginate microbeads were fabricated by dropping a 2% (w/v) alginate solution containing TMSCs into a 5% CaCl2 solution and then differentiated into parathyroid-like cells using activin A and sonic hedgehog for 7 days. The protein expression of PTH, a specific marker of the parathyroid gland, was significantly higher in differentiated alginate microbeads with TMSCs (Al-dT) compared with in undifferentiated alginate microbeads with TMSCs. For in vivo experiments, we created the hypoparathyroidism animal model by parathyroidectomy (PTX) and implanted alginate microbeads in the dorsal interscapular region. The PTX rats with Al-dT (PTX+Al-dT) showed the highest survival rate and weight change and a gradual increase in serum intact PTH levels. We also detected a higher expression of PTH in retrieved tissues of PTX+Al-dT using immunofluorescence analysis. This study demonstrates that alginate microbeads are potential a new tool as a surgically scalable therapy for treating hypoparathyroidism.

Size and Shape Control of Ice Crystals by Amphiphilic Block Copolymers and Their Implication in the Cryoprotection of Mesenchymal Stem Cells

Precise control over the size and shape of ice crystals is a key factor to consider in designing antifreezing and cryoprotecting molecules for cryopreservation of cells. Here, we report that a poly(ethylene glycol)-poly(l-alanine) (PEG-PA) block copolymer exhibits excellent cryoprotecting properties for stem cells and antifreezing properties for water. As the molecular weight of PA increased from 500, 760, and 1750 Da (P1, P2, and P3) at the same PEG molecular weight of 5000 Da, the β-sheet content decreased and α-helix content increased. Comparing P2 (PEG-PA; 5000-760) and P4 (PEG-PA: 1000-750), β-sheets increased as the PEG block length decreased. The critical micelle concentration of the PEG-PA block copolymers was in a range of 0.5-3.0 mg/mL and was proportional to the hydrophobicity of the PEG-PA block copolymers. The P1, P2, and P3 self-assembled into spherical micelles, whereas P4 formed micelles with cylindrical morphology. The difference in the block copolymer structure affected ice recrystallization inhibition (IRI) activity and cryopreservation of cells. IRI activity was assayed via mean largest grain size (MLGS), and interactions between polymers and ice crystal surfaces were studied by dynamic ice-shaping studies. The MLGS decreased to 58 → 53 → 45 → 35 → 23% of that of PBS, as the polymer (PEG-PA 5000-500) concentration increased from 0.0 (PBS; control) → 1.0 → 5.0 → 10 → 30 → 50 mg/mL. The MLGS of PEG 5k solutions (negative control) decreased to 74 → 71 → 64 → 44 → 37% of that of PBS in the same concentration range. P3 and P4 with a longer hydrophobic PA block developed elongated ice crystals at above 30 mg/mL. The dynamic ice-shaping study exhibited that ice crystals became needle-shaped, as the hydrophobicity of the polymer increased as in P2-P4. The cell recovery in the P1 system after cryopreservation at -196 °C for 7 days was 87% of that of the dimethyl sulfoxide (DMSO) 10% system (positive control). The cell recovery was 48% for the P2 system and drastically decreased to less than 30% of that of the DMSO 10% system in the P3, P4, PEG 5k, PEG 1k, PVA 80H, and PVA 100H systems. Current studies suggest that IRI activity, round ice crystal shaping, and membrane stabilization activity of P1 cooperatively provide excellent cell recovery among the candidate systems. Recovered stem cells exhibited excellent proliferation and multilineage differentiation into osteocytes, chondrocytes, and adipocytes. To conclude, the PEG-PA (5000-500) block copolymer is suggested to be a promising antifreezing cryoprotectant for stem cells.

Mesenchymal stem/stromal cell-based therapy for the treatment of rheumatoid arthritis: An update on preclinical studies

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovial inflammation and progressive joint destruction and is a primary cause of disability worldwide. Despite the existence of numerous anti-rheumatic drugs, a significant number of patients with RA do not respond or are intolerant to current treatments. Mesenchymal stem/stromal cell (MSCs) therapy represents a promising therapeutic tool to treat RA, mainly attributable to the immunomodulatory effects of these cells. This review comprises a comprehensive analysis of the scientific literature related to preclinical studies of MSC-based therapy in RA to analyse key aspects of current protocols as well as novel approaches which aim to improve the efficacy of MSC-based therapy.

Therapeutic Effects of Tonsil-derived Mesenchymal Stem Cells in an Atopic Dermatitis Mouse Model

BACKGROUND/AIM

Mesenchymal stem cells (MSCs) have been suggested as an alternative therapeutic option in atopic dermatitis. Palatine tonsils are lymphoepithelial tissue located around the oropharynx and have been proposed as one of the important alternative sources of MSCs. The purpose of this study was to evaluate the protective and therapeutic effects of tonsil-derived MSCs (TMSCs) in a 2,4-dinitrofluorobenzene (DNFB)-induced mouse model of atopic dermatitis (AD).

MATERIALS AND METHODS

The effect of TMSCs was evaluated in 20 C57BL/6J mice that were randomly divided into four groups (normal, DNFB-PBS, DNFB-TMSC7, and DNFB-TMSC16 group). TMSCs were subcutaneously injected into DNFB-sensitized mice on day 7 (DNFB-TMSC7 group) and day 16 (DNFB-TMSC16 group). Several parameters of inflammation were assessed.

RESULTS

Subcutaneously injected TMSCs significantly improved the inflammatory symptoms in a DNFB-induced AD model mice, particularly showing therapeutic effects rather than protective effects. TMSC treatment inhibited T-cell-mediated inflammatory responses by decreasing the levels of IL-6, IL-1β, TNF-α (Th1 cell marker), IL-4 (Th2 cell marker), and B-cell-mediated serum IgE. In contrast, TMSCs enhanced the anti-inflammatory cytokine TGF-β.

CONCLUSION

In vitro and in vivo results suggest that TMSC treatment improved inflammatory skin lesions in the DNFB-induced AD mice model via immunomodulatory effects of the TMSCs. TMSCs inhibit T-cell and B-cell mediated responses, and enhance the anti-inflammatory responses.

Tonsil-derived mesenchymal stem cells enhance allogeneic bone marrow engraftment via collagen IV degradation

BACKGROUND

Co-transplantation of bone marrow cells (BMCs) and mesenchymal stem cells (MSCs) is used as a strategy to improve the outcomes of bone marrow transplantation. Tonsil-derived MSCs (TMSCs) are a promising source of MSCs for co-transplantation. Previous studies have shown that TMSCs or conditioned media from TMSCs (TMSC-CM) enhance BMC engraftment. However, the factors in TMSCs that promote better engraftment have not yet been identified.

METHODS

Mice were subjected to a myeloablative regimen of busulfan and cyclophosphamide, and the mRNA expression in the bone marrow was analyzed using an extracellular matrix (ECM) and adhesion molecule-targeted polymerase chain reaction (PCR) array. Nano-liquid chromatography with tandem mass spectrometry, real-time quantitative PCR, western blots, and enzyme-linked immunosorbent assays were used to compare the expression levels of metalloproteinase 3 (MMP3) in MSCs derived from various tissues, including the tonsils, bone marrow, adipose tissue, and umbilical cord. Recipient mice were conditioned with busulfan and cyclophosphamide, and BMCs, either as a sole population or with control or MMP3-knockdown TMSCs, were co-transplanted into these mice. The effects of TMSC-expressed MMP3 were investigated. Additionally, Enzchek collagenase and Transwell migration assays were used to confirm that the collagenase activity of TMSC-expressed MMP3 enhanced BMC migration.

RESULTS

Mice subjected to the myeloablative regimen exhibited increased mRNA expression of collagen type IV alpha 1/2 (Col4a1 and Col4a2). Among the various extracellular matrix-modulating proteins secreted by TMSCs, MMP3 was expressed at higher levels in TMSCs than in other MSCs. Mice co-transplanted with BMCs and control TMSCs exhibited a higher survival rate, weight recovery, and bone marrow cellularity compared with mice co-transplanted with BMCs and MMP3-knockdown TMSCs. Control TMSC-CM possessed higher collagenase activity against collagen IV than MMP3-knockdown TMSC-CM. TMSC-CM also accelerated BMC migration by degrading collagen IV in vitro.

CONCLUSIONS

Collectively, these results indicate that TMSCs enhance BMC engraftment by the secretion of MMP3 for the modulation of the bone marrow extracellular matrix.

Advances in mesenchymal stem cell transplantation for the treatment of osteoporosis

Osteoporosis is a systemic metabolic bone disease with characteristics of bone loss and microstructural degeneration. The personal and societal costs of osteoporosis are increasing year by year as the ageing of population, posing challenges to public health care. Homing disorders, impaired capability of osteogenic differentiation, senescence of mesenchymal stem cells (MSCs), an imbalanced microenvironment, and disordered immunoregulation play important roles during the pathogenesis of osteoporosis. The MSC transplantation promises to increase osteoblast differentiation and block osteoclast activation, and to rebalance bone formation and resorption. Preclinical investigations on MSC transplantation in the osteoporosis treatment provide evidences of enhancing osteogenic differentiation, increasing bone mineral density, and halting the deterioration of osteoporosis. Meanwhile, the latest techniques, such as gene modification, targeted modification and co-transplantation, are promising approaches to enhance the therapeutic effect and efficacy of MSCs. In addition, clinical trials of MSC therapy to treat osteoporosis are underway, which will fill the gap of clinical data. Although MSCs tend to be effective to treat osteoporosis, the urgent issues of safety, transplant efficiency and standardization of the manufacturing process have to be settled. Moreover, a comprehensive evaluation of clinical trials, including safety and efficacy, is still needed as an important basis for clinical translation.

sEVs from tonsil-derived mesenchymal stromal cells alleviate activation of hepatic stellate cells and liver fibrosis through miR-486-5p

Mesenchymal stromal cells (MSCs) are considered as a promising therapeutic tool for liver fibrosis, a main feature of chronic liver disease. Because small extracellular vesicles (sEVs) harboring a variety of proteins and RNAs are known to have similar functions with their derived cells, MSC-derived sEVs carry out the regenerative capacities of MSCs. Human tonsil-derived MSCs (T-MSCs) are reported as a novel source of MSCs, but their effects on liver fibrosis remain unclear. In the present study, we investigated the effects of T-MSC-derived sEVs on liver fibrosis. The expression of profibrotic genes decreased in human primary hepatic stellate cells (pHSCs) co-cultured with T-MSCs. Treatment of T-MSC-sEVs inactivated human and mouse pHSCs. Administration of T-MSC-sEVs ameliorated hepatic injuries and fibrosis in chronically damaged liver induced by carbon tetrachloride (CCl₄). miR-486-5p highly enriched in T-MSC-sEVs targeting the hedgehog receptor, smoothened (Smo), was upregulated, whereas Smo and Gli2, the hedgehog target gene, were downregulated in pHSCs and liver tissues treated with T-MSC-sEVs or miR-486-5p mimic, indicating that sEV-miR-486 inactivates HSCs by suppressing hedgehog signaling. Our results showed that T-MSCs attenuate HSC activation and liver fibrosis by delivering sEVs, and miR-486 in the sEVs inactivates hedgehog signaling, suggesting that T-MSCs and their sEVs are novel anti-fibrotic therapeutics for treating chronic liver disease.

Thermogelling Inclusion Complex System for Fine-Tuned Osteochondral Differentiation of Mesenchymal Stem Cells

How to control osteochondral differentiation of mesenchymal stem cells at a proper stage is a key issue for articular cartilage regeneration. To solve this problem, injectable scaffolds with different chemical functional groups were designed by introducing one equivalent of α-cyclodextrin (α-CD) carboxylate and α-CD phosphate along poly(ethylene glycol)-poly(l-alanine) (PEG-L-PA) block copolymers. Dynamic light scattering, transmission electron microscopy images, and two-dimensional NMR spectra indicated that the PEG-L-PA block copolymers formed inclusion complexes with α-CD derivatives. Aqueous solutions of PEG-L-PA block copolymers (P), α-CD carboxylate/PEG-L-PA block copolymers (PCC), and α-CD phosphate/PEG-L-PA block copolymers (PCP) underwent sol-to-gel transition as the temperature increased. The storage moduli of P, PCC, and PCP gels ranged from 1000 to 1300 Pa at 37 °C. Tonsil-derived mesenchymal stem cells (TMSCs) were incorporated in situ in the gel during thermogelation of P, PCC, and PCP, which became the three-dimensional cell culture systems with different functional groups. After 21 days of incubation of TMSCs in the P, PCC, and PCP systems, the chondrogenic differentiation biomarker of type II collagen significantly increased in the P system, whereas the osteogenic biomarkers of osteocalcin and runt-related transcription factor 2 significantly increased in the PCP system. Both chondrogenic and osteogenic biomarkers were highly expressed in the PCC system. This study proved that thermogelling inclusion complex systems consisting of PEG-L-PA block copolymers and α-CD derivatives could be an excellent injectable matrix for fine-controlling osteochondral differentiation of mesenchymal stem cells.

Conditioned Medium from Human Tonsil-Derived Mesenchymal Stem Cells Enhances Bone Marrow Engraftment via Endothelial Cell Restoration by Pleiotrophin

Cotransplantation of mesenchymal stem cells (MSCs) with hematopoietic stem cells (HSCs) has been widely reported to promote HSC engraftment and enhance marrow stromal regeneration. The present study aimed to define whether MSC conditioned medium could recapitulate the effects of MSC cotransplantation. Mouse bone marrow (BM) was partially ablated by the administration of a busulfan and cyclophosphamide (Bu–Cy)-conditioning regimen in BALB/c recipient mice. BM cells (BMCs) isolated from C57BL/6 mice were transplanted via tail vein with or without tonsil-derived MSC conditioned medium (T-MSC CM). Histological analysis of femurs showed increased BM cellularity when T-MSC CM or recombinant human pleiotrophin (rhPTN), a cytokine readily secreted from T-MSCs with a function in hematopoiesis, was injected with BMCs. Microstructural impairment in mesenteric and BM arteriole endothelial cells (ECs) were observed after treatment with Bu–Cy-conditioning regimen; however, T-MSC CM or rhPTN treatment restored the defects. These effects by T-MSC CM were disrupted in the presence of an anti-PTN antibody, indicating that PTN is a key mediator of EC restoration and enhanced BM engraftment. In conclusion, T-MSC CM administration enhances BM engraftment, in part by restoring vasculature via PTN production. These findings highlight the potential therapeutic relevance of T-MSC CM for increasing HSC transplantation efficacy.

Wound Healing Promoting Activity of Tonsil-Derived Stem Cells on 5-Fluorouracil-Induced Oral Mucositis Model

BACKGROUND

We first determined the efficacy of lesional injection of tonsil-derived MSCs (mesenchymal stem cells) for the treatment of 5-fluorouracil induced oral mucositis.

METHODS

Oral mucositis was induced in hamsters by administration of 5-fluorouracil (day 0, 2, 4) followed by mechanical trauma (day 1, 2, 4). The experimental groups included MT (mechanical trauma only), 5-FU + MT (mechanical trauma with 5-fluorouracil administration), TMSC (mechanical trauma with 5-fluorouracil administration, tonsil-derived mesenchymal stem cells injection), DEXA (mechanical trauma with 5-fluorouracil administration, dexamethasone injection), and saline (mechanical trauma with 5-fluorouracil administration, saline injection).

RESULTS

On day 10, gross and histologic analyses showed that nearly complete healing and epithelialization of the cheek mucosa of the TMSC group, whereas the other groups showed definite ulcerative lesions. Compared with the MT and DEXA groups, CD31 expression was greater in the TMSC group on days 10 and 14. Tendency towards a decrease in MMP2 expression with the time in the TMSC group was observed. In addition, the TMSC group showed higher expression of TGF-β, and NOX4 on day 10 compared with the other groups. Scratch assay demonstrated that the conditioned media harvested from tonsil-derived MSCs significantly increased migratory efficacy of NIH3T3 cells. Transwell assay showed that the preferential migration of tonsil-derived MSCs to the wound area.

CONCLUSION

Intralesional administration of tonsil-derived MSCs may accelerate wound healing of 5-fluorouracil induced oral mucositis by upregulating neovascularization and effective wound contraction. In addition, tonsil-derived MSCs might contribute to oral ulcer regeneration via the stimulation of fibroblast proliferation and migration.