Effects of Violet and IR LED Light on mast cell degranulation: in vivo study in a murine model.

The aim of this study was to evaluate the influence of IR (λ850 ± 10 nm) and violet (λ405 ± 10 nm) LED phototherapy on total mast cells counts and its ability to influence mast cell degranulation. For this, 27 Wistar rats were used and were randomly distributed into three groups: control, IR LED, and violet LED. When indicated, irradiation done and they were sacrificed, had their tongue removed immediately, 20-min, 45-min, and 2-h after irradiation. Samples were processed to wax, cut, and stained with Toluidine Blue. Intact and degranulated mast cells were counted under light microscopy, and statistical analysis was carried out. In the superficial connective tissue and muscular tissues, violet LED light caused a significant increase in both total number and degranulated mast cells when compared to the control group immediately after irradiation. The degranulation indexes were higher in the groups irradiated with Violet light, both in superficial connective tissue and muscular tissues in relation to the timing. Irradiation with IR LED caused immediate increase in the total number and degranulated of mast cells when compared to the control group only in the superficial connective tissue. In all times observed, the highest total amount of mast cells was seen immediately after irradiation, except in the muscular tissue, which presented the highest amount after 20-min. It was concluded that IR and violet LED light were able to increase the number of mast cells and inducing degranulation in oral mucosa. However, considering that violet LED light can be harmful in periodontal disease, it seems that the use of IR LED light could be the best option in Dentistry.

Mast cell degranulation and vascular endothelial growth factor expression in mouse skin following ionizing irradiation.

The present study aimed to identify the mechanisms underlying the increase in vascular permeability in mouse skin following irradiation. The left ears of C3H mice were subjected to 2 and 15 Gy of radiation in a single exposure. At 24 h after irradiation, the ears were excised and tissue sections were stained with toluidine blue to assess mast cell degranulation. Vascular endothelial growth factor (VEGF) expression was assessed via immunohistochemistry and western blotting. Approximately 5% (3%-14%) (mean [95% CI]) of mast cells in the skin of control mice were degranulated; moreover, at 24 h after 2 Gy irradiation, this value increased to approximately 20% (17%-28%). Mast cell degranulation by 15 Gy irradiation (32% [24%-40%]) was greater than that by 2 Gy irradiation. Significant differences were observed in mast cell degranulation among the control, 2 Gy and 15 Gy groups (p = 0.012). Furthermore, VEGF-positive reactions were observed in the cytoplasm of scattered fibroblasts in the dermis. In immunohistochemistry tests, VEGF expression at 24 h after irradiation increased slightly in the 2 Gy group compared to that in the control group, whereas no difference in VEGF expression was observed in the 15 Gy group compared to that in the control group. Expression of VEGF in western blots was consistent with that in immunohistochemistry. In conclusion, mast cell degranulation was increased in mouse skin at 24 h after irradiation in a dose-dependent manner. In contrast, VEGF expression was slightly increased following only low-dose (2 Gy) irradiation.

Combined effects of photobiomodulation and curcumin on mast cells and wound strength in wound healing of streptozotocin-induced diabetes in rats.

We investigated the probable involvement of mast cell degranulation and their numbers in the remodeling step of wound healing in a diabetic ischemic skin wound model treated with photobiomodulation plus curcumin. A total of 108 adult male Wistar rats were randomized into one healthy control and five diabetic groups. Type I diabetes was inflicted in 90 of the 108 rats. After 1 month, an excisional wound was generated in each of the 108 rats. There were one healthy group (group 1) and five diabetic groups as follows: group 2 was the untreated diabetic control group and group 3 rats were treated with sesame oil. Rats in group 4 were treated with photobiomodulation (890 nm, 890 ± 10 nm, 80 Hz, 0.2 J/cm2) and those in group 5 received curcumin dissolved in sesame oil. Group 6 rats were treated with photobiomodulation and curcumin. We conducted stereological and tensiometric tests on days 4, 7, and 15 after treatment. The results indicated that photobiomodulation significantly improved wound strength in the diabetic rats and significantly decreased the total numbers of mast cells. The diabetic control group had significantly reduced tensiometric properties of the healing wounds and a significant increase in the total numbers of mast cells. Photobiomodulation significantly improved the healing process in diabetic animals and significantly decreased the total number of mast cells. The increased numbers of mast cells in the diabetic control group negatively affected tensiometric properties of the ischemic skin wound.

Surface-enhanced Raman spectroscopy analysis of mast cell degranulation induced by low-intensity laser.

Mast cell (MC) degranulation is an important step in the healing process. In this study, silver-nanoparticles-based surface-enhanced Raman spectroscopy (SERS) was used to investigate the spectral characteristics of degranulation of MCs activated by low-intensity laser. The significant spectral changes, such as Raman peak intensities, suggested the concentration variation of some degranulated substances. The Raman intensity ratio of 799-554 cm-1 could be used as a potential internal indicator for the degranulation degree of MCs. Principal component analysis (PCA) was employed to reduce the high dimension of spectra into a few principal components (PCs) while retaining the most diagnostically significant information for sample differentiation. Using the diagnostically significant PC scores (P < 0.05), linear discriminate analysis (LDA) was applied to identify different cell degranulation groups with high sensitivity, specificity and accuracy. This exploratory work demonstrates that SERS technique combined with a PCA-LDA algorithm possesses great potential for developing a label-free, comprehensive, non-invasive and accurate method for measuring MC degranulation.

Impact of Photobiomodulation and Condition Medium on Mast Cell Counts, Degranulation, and Wound Strength in Infected Skin Wound Healing of Diabetic Rats.

Background: Numerous people suffer from diabetes mellitus (DM) and resultant diabetic foot ulcers (DFU), which lack effective treatment. Photobiomodulation (PBM) has accelerated wound healing in diabetic animals and patients in some studies. However, there is scant information on the number and activation state of skin mast cells (MCs) in PBM-treated diabetic wounds. Objective: We intend to assess the influence of the number of MCs and degranulation in the remodeling step of an infected wound model on wound strength and its microbial flora in a type 1 DM (T1DM) rat model by administration of PBM, condition medium (CM) derived from human bone marrow mesenchymal stem cells (hBMMSCs), and the combination of PBM+CM. Methods: We prepared CM by culturing hBMMSCs. T1DM was induced in 72 rats and, after 1 month, we created one excisional wound in each rat. All wounds were infected with methicillin-resistant Staphylococcus aureus (MRSA). We divided the rats into four groups: (n = 18): (i) control; (ii) PBM; (iii) CM, and (iv) PBM+CM. On days 4, 7, and 15, we conducted microbiological, tensiometrical, and stereological analyses. The type of MCs (T1MCs, T2MCs, or T3MCs) and total number of MCs (TOMCs) were counted by light microscopy. Results: On day 15, the PBM+CM, PBM, and CM groups had significantly increased wound strength compared with the control group. There was a significant decrease in colony-forming units (CFU) at all time points in the PBM+CM and PBM groups. The PBM+CM and PBM groups had more stable MCs (T1MCs), less significant degranulated MCs (T2MCs), less significant disintegrated MCs (T3MCs), and less significant TOMCs compared with the control group at all time points. Conclusions: PBM+CM and PBM treatments significantly increased the healing process in an ischemic and MRSA-infected wound model of T1DM rats. PBM+CM and PBM significantly decreased both TOMCs and their degranulation, and significantly decreased CFU.

Transepidermal UV radiation of scalp skin ex vivo induces hair follicle damage that is alleviated by the topical treatment with caffeine.

OBJECTIVES: Although the effect of ultraviolet radiation (UVR) on human skin has been extensively studied, very little is known on how UVR impacts on hair follicle (HF) homeostasis. Here, we investigated how solar spectrum UVR that hits the human skin surface impacts on HF biology, and whether any detrimental effects can be mitigated by a widely used cosmetic and nutraceutical ingredient, caffeine. METHODS: Human scalp skin with terminal HFs was irradiated transepidermally ex vivo using either 10 J/cm2 UVA (340-440 nm) + 20 mJ/cm2 UVB (290-320 nm) (low dose) or 50 J/cm2 UVA + 50 mJ/cm2 UVB (high dose) and organ-cultured under serum-free conditions for 1 or 3 days. 0.1% caffeine (5.15 mmol/L) was topically applied for 3 days prior to UV exposure with 40 J/cm2 UVA + 40 mJ/cm2 UVB and for 3 days after UVR. The effects on various toxicity and vitality read-out parameters were measured in defined skin and HF compartments. RESULTS: Consistent with previous results, transepidermal UVR exerted skin cytotoxicity and epidermal damage. Treatment with high and/or low UVA+UVB doses also induced oxidative DNA damage and cytotoxicity in human HFs. In addition, it decreased proliferation and promoted apoptosis of HF outer root sheath (ORS) and hair matrix (HM) keratinocytes, stimulated catagen development, differentially regulated the expression of HF growth factors, and induced perifollicular mast cell degranulation. UVR-mediated HF damage was more severe after irradiation with high UVR dose and reached also proximal HF compartments. The topical application of 0.1% caffeine did not induce skin or HF cytotoxicity and stimulated the expression of IGF-1 in the proximal HF ORS. However, it promoted keratinocyte apoptosis in selected HF compartments. Moreover, caffeine provided protection towards UVR-mediated HF cytotoxicity and dystrophy, keratinocyte apoptosis, and tendential up-regulation of the catagen-promoting growth factor. CONCLUSION: Our study highlights the clinical relevance of our scalp UV irradiation ex vivo assay and provides the first evidence that transepidermal UV radiation negatively affects important human HF functions. This suggests that it is a sensible prophylactic strategy to integrate agents such as caffeine that can act as HF photoprotectants into sun-protective cosmeceutical and nutraceutical formulations.

OBJECTIFS: Alors que l'effet de rayons ultraviolets (RUV) sur la peau humaine a été largement étudié, on sait très peu de choses de l'impact des UV sur l'homéostasie du follicule pileux (FP). Ici, nous avons étudié l'effet du spectre des RUV solaires qui atteignent la surface de la peau humaine sur la biologie du FP, et si tout effet nocif peut être atténué par de la caféine, un ingrédient cosmétique et neutraceutique largement utilisé. MÉTHODES: Une peau de cuir chevelu humain avec ses FP terminaux a été irradiée ex vivo via l'épiderme soit par 10 J/cm2 d'UVA (340-440 nm) + 20 mJ/cm2 d'UVB (290-320 nm) (dose faible) soit par 50 J/cm2 d'UVA + 50 mJ/cm2 d'UVB (dose élevée) et placée en culture sans sérum pendant 1 ou 3 jours. 0,1% (5,15 mM) de caféine a été appliquée par voie topique pendant 3 jours avant l'exposition aux UV à raison de 40 J/cm2 d'UVA + 40 mJ/cm2 UVB et pendant 3 jours après l'exposition aux RUV. Les effets sur divers paramètres de toxicité et de vitalité ont été mesurés au niveau de compartiments définis de la peau et des FP. RÉSULTATS: Cohérent avec les résultats précédents, les RUV transépidermique ont exercé une cytotoxicité au niveau de la peau et des lésions épidermiques. Le traitement par des doses élevées et/ou faibles d'UVA+UVB a également induit des lésions oxydatives de l'ADN et une cytotoxicité au niveau des FP humains. En outre, il a diminué la prolifération et favorisé l'apoptose de la gaine externe de la racine (ORS) du FP et des kératinocytes de la matrice des cheveux (MC), a stimulé le développement de la phase catagène, a régulé de manière différentielle l'expression des facteurs de croissance des FP, et induit une dégranulation périfolliculaire des mastocytes. Les lésions du FP médiées par les RUV étaient plus graves après une irradiation par dose élevée de RUV et atteignaient également les compartiments proximaux du FP. L'application topique de 0,1 % de caféine n'a pas induit de cytotoxicité de la peau ou du FP et a stimulé l'expression d'IGF-1 dans la partie proximale de l'ORS du FP. Cependant, elle a promu l'apoptose des kératinocytes dans certains compartiments de FP. En outre, la caféine a fourni une protection des FP contre la cytotoxicité et la dystrophie médiées par les RUV, l'apoptose des kératinocytes et une régulation à tendance positive de l'effet catagène induit par le facteur de croissance. CONCLUSION: Notre étude souligne la pertinence clinique de notre dosage d'irradiation UV ex vivo du cuir chevelu et fournit la première preuve que le rayonnement UV transépidermique affecte négativement d'importantes fonctions du FP chez l'homme. Cela suggère que l'intégration d'agents photoprotecteurs des FP tels que la caféine dans les formulations cosmétiques et nutraceutiques des écrans solaires pourrait constituer une stratégie prophylactique sensée.

Effects of Photobiomodulation on Degranulation and Number of Mast Cells and Wound Strength in Skin Wound Healing of Streptozotocin-Induced Diabetic Rats.

BACKGROUND: A lack of effective treatments still exists for patients suffering from diabetes mellitus. Photobiomodulation is proved as a beneficial therapeutic modality for wounds. OBJECTIVE: The aim of this study is to examine the effect of degranulation of mast cells and total number of mast cells in the remodeling step of an ischemic model of wound healing under the influence of photobiomodulation and conditioned medium (CM) from human bone marrow-derived mesenchymal stem cells (hBM-MSCs-CM), or CM, administered alone and or in combination. MATERIALS AND METHODS: Initially, type 1 diabetes mellitus was induced in 72 male adult rats. Then, after a month, one incision was made on the back of each rat. Subsequently, the rats were divided into four groups. The first group was considered as the control (placebo) group, the second group received CM, the third group received photobiomodulation, and the fourth group received photobiomodulation+CM. On days 4, 7, and 15, samples were extracted from the wound for histological and tensiometric examinations. The total number of mast cells, including the three types of mast cells, was counted by the stereological methods. The tensiometric properties of the repairing tissue were examined. RESULTS: The administration of photobiomodulation and CM, alone or in combination, significantly increased the tensiometric properties within the healing wounds. Histologically, photobiomodulation+CM, CM, and photobiomodulation groups showed a significant decrease in the three types of mast cells and in the total number of mast cells compared with the control group on day 15. CONCLUSIONS: We conclude that photobiomodulation and CM alone and or in combination significantly accelerated the healing process in a rat with a diabetic and ischemic wound, and significantly decreased the total number of mast cells and degranulation of mast cells. We suggest that the increased number of type 2 mast cells in the control group adversely affected the tensiometric properties of wounds in this group.

The Suppressive Activity of Fucofuroeckol-A Derived from Brown Algal Ecklonia stolonifera Okamura on UVB-Induced Mast Cell Degranulation.

UV light, especially UVB, is known as a trigger of allergic reaction, leading to mast cell degranulation and histamine release. In this study, phlorotannin Fucofuroeckol-A (F-A) derived from brown algal Ecklonia stolonifera Okamura was evaluated for its protective capability against UVB-induced allergic reaction in RBL-2H3 mast cells. It was revealed that F-A significantly suppress mast cell degranulation via decreasing histamine release as well as intracellular Ca2+ elevation at the concentration of 50 µM. Moreover, the inhibitory effect of F-A on IL-1ß and TNF-α productions was also evidenced. Notably, the protective activity of F-A against mast cell degranulation was found due to scavenging ROS production. Accordingly, F-A from brown algal E. stolonifera was suggested to be promising candidate for its protective capability against UVB-induced allergic reaction.

Expansion of cytotoxic natural killer cells using irradiated autologous peripheral blood mononuclear cells and anti-CD16 antibody.

Natural killer (NK) cells are considered a promising strategy for cancer treatment. Various methods for large-scale NK cell expansion have been developed, but they should guarantee that no viable cells are mixed with the expanded NK cells because most methods involve cancer cells or genetically modified cells as feeder cells. We used an anti-CD16 monoclonal antibody (mAb) and irradiated autologous peripheral blood mononuclear cells (PBMCs) (IrAPs) to provide a suitable environment (activating receptor-ligand interactions) for the NK cell expansion. This method more potently expanded NK cells, and the final product was composed of highly purified NK cells with lesser T-cell contamination. The expanded NK cells showed greater upregulation of various activation receptors, CD107a, and secreted larger amounts of interferon gamma. IrAPs expressed NKG2D ligands and CD48, and coengagement of CD16 with NKG2D and 2B4 caused potent NK cell activation and proliferation. The expanded NK cells were cytotoxic toward various cancer cells in vitro and in vivo. Moreover, irradiation or a chemotherapeutic drug further enhanced this antitumor effect. Therefore, we developed an effective in vitro culture method for large-scale expansion of highly purified cytotoxic NK cells with potent antitumor activity using IrAPs instead of cancer cell-based feeder cells.

Effect of low energy light irradiation by light emitting diode on U937 cells.

Photobiomodulation (PBM) can induce a set of different biological modulators either in vitro or in vivo. Experimental evidence has highlighted the role of light effects on the mechanisms related to inflammation, apoptosis and autophagy. The goal of this project was the evaluation of PBM on U937, an established cell line of histiocytic lymphoma origin. Several aspects of modulation of proinflammatory pathways were analyzed and autophagic and proapoptotic mechanisms related to low laser light exposure of cells were studied. As a source of low energy light emission, we used an NIR-LED device, characterized by an 880 nm-wavelength as light source. Flow cytometry analysis was performed on supernatants of controls and treated U937 cells to detect inflammatory cytokine levels. In order to evaluate NF-kB and caspase3 expressions, Western blot analysis was performed according to standard procedures. In this report, we show the effect of PBM on a monocyte/macrophage established tumor cell line (U-937). We demonstrate that LED exposure, in the presence or absence of lipopolysaccharide (LPS), activates cell degranulation, increased expression of Interleukin-8 (IL-8) and modulation of beta galactosidase activity. Evidence shows that the well-known pro-inflammatory nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) and the apoptotic marker (caspase3/cleaved-caspase3 ratio) are up-regulated in response to a proinflammatory biochemical pathway.

Effect of 5-ALA-mediated photodynamic therapy on mast cell and microvessels densities present in oral premalignant lesions induced in rats.

Acute inflammatory response after photodynamic therapy is frequently described, and increase on mast cell degranulation is also present during this process. The mast cell activation may improve angiogenesis, and this fact has been associated with progression of oral premalignant lesions (OPL). The aim of this study was to evaluate whether photodynamic therapy (PDT) increases mast cell density (MCD) and microvessels density (MVD) in 4-nitroquinoline-1-oxide(4NQO)-induced OPL in rats. 4NQO-induced OPL were treated or not with 5-ALA followed by laser irradiation (PDT group and 4NQO groups, respectively). Mast cells and CD34+ microvessels were counted. Both PDT and 4NQO groups had MCD and MVD that were higher than normal mucosa (p b 0.05). The 4NQO group had the lowest number of non-degranulated MCD in comparison to experimental periods of PDT (PDT 6 h ­ p=0.020; 24 h ­ p=0.016; 48 h ­ p=0.003; 72 h ­ p=0.033). Only in the PDT group did MCD and MVD have a significant correlation (r= 0.6219, p = 0.010). 5-ALA-mediated PDT modified the MCD and MVD in the induced OPL, leading to degranulation of mast cells and angiogenesis. A PDT protocol with an efficient eradication of the OPL must be adopted considering the angiogenesis potential associated with the mast cell activation after the therapy.

Tea polyphenols protect against irradiation-induced injury in submandibular glands' cells: a preliminary study.

AIM: To study the protective effect of tea polyphenols (TPs) on submandibular glands affected by radiation injury. METHODS: Sixty rats were randomly divided into radiation group (R-group, N = 30) and TP-pre-treated-radiation group (TPR-group, N = 30). The rats were intragastrically administered with TP or normal sodium from 14 days before radiation, continuously daily, until the experiment. All the rats in both groups were irradiated with a single exposure dose of 15 Gy gamma rays that were delivered to the head and neck areas. Ten rats of each group were anatomised on the 3rd, 6th and 30th day after irradiation, respectively. The submandibular glands of the rats were removed for the study. The morphologic changes of the submandibular glands were observed by transmission electron microscopy (TEM). The terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP)-biotin nick-end labelling (TUNEL) method was used to detect apoptosis of the submandibular glands' cells. RESULTS: Electron microscope observation of the submandibular glands showed that the lesions of the TPR-group were mild. Change in apoptosis of the cells was not obvious compared with the R-group. The cell apotosis was typical after irradiation in the R-group. Apoptosis index that was detected in the cells of submandibular glands of the TPR-group was statistically significantly decreased compared with the R-group (P < 0.01) on the 3rd, 6th and 30th day after irradiation. CONCLUSION: TP could protect submandibular glands from radiation injuries, and the protection mechanism may be realised by anti-apoptosis.

Adaptive responses of individual tissue structures of rat gingival mucosa to exposure to low-intensity 890-nm laser irradiation.

Adaptive reactions develop in rat gingival mucosa 1 min after single exposure to low-intensity 890-nm laser: the number of mast cells, degree and index of their degranulation, the diameter of blood vessels and their total area considerably increased. These parameters returned to normal after 1 day, while on days 3-7 they were below the control.

Combined exposure of peripubertal male rats to the endocrine-disrupting compound atrazine and power-frequency electromagnetic fields causes degranulation of cutaneous mast cells: a new toxic environmental hazard?

The effects of single and combined treatments of the endocrine-disrupting compound atrazine and the power-frequency electromagnetic fields (EMFs) were investigated on cutaneous mast cells in juvenile/peripubertal male Wistar rats. Animals were divided into six groups: (1) 4 h/day exposure to EMFs (50 Hz), (2) 20 mg/kg of body weight (bw) of atrazine, (3) 200 mg/kg bw of atrazine, (4) EMFs with 20 mg/kg bw of atrazine, (5) EMFs with 200 mg/kg bw of atrazine, and (6) control. Both the atrazine and the combined treatments, but not the single EMF exposure, increased the number of degranulated mast cells. Statistically significant differences were demonstrated between the control and both of the combined treatments (p<0.01 and p<0.001, respectively). Additionally, low and high doses of atrazine combined with the EMFs were found significantly different when compared to the EMF group alone (both at p<0.001). Considering the biological importance of mast cells in cutaneous immune reactions, future studies should reveal whether combined exposures to chemical and physical environmental agents pose a serious health risk.

[Relationship between laser acupuncture analgesia and the function of mast cells].

OBJECTIVE: To observe the analgesic effects of single-and combined-laser irradiation with low-intensity applied at "Zusanli" (ST 36) in rats, and their relation to degranulation of mast cells. METHODS: Sixty-six SD rats were randomly divided into 6 groups: normal control group (Group NC), model control group (Group MC), sham irradiation group (Group SI), 10.6 microm laser irradiation group (Group 10.6 microm LI), 650 nm laser irradiation group (Group 650 nm LI) and combined (10.6 microm + 650 nm) laser irradiation group (Group CLI). Complete Freund's Adjuvant (0.05 mL) was injected into the left ankle joints of all the rats except those in Group NC to cause acute adjuvant-induced arthritis. In treatment, laser irradiation was applied at "Zusanli" (ST 36) for 30 minutes in all the rats except those in Group NC and Group MC. The paw withdrawal latency (PWL) to radian heat was used to compare analgesic effects among the groups. By means of toluidine blue, dyed slices of local tissues of "Zusanli" (ST 36) were used to observe changes of mast cell degranulation before and after laser irradiation. RESULTS: The pain thresholds to irradiation of the rats in Group 650 nm LI and Group CLI were significantly higher than those in Group MC and Group SI (P < 0.01), and the mast cell degranulation rate in Group 650 nm LI and Group CLI were also significantly higher than that in Group MC and Group SI (P < 0.001). The pain threshold and mast cell degranulation rate in Group 10. 6 microm LI were not significantly different from those in Group MC and Group SI. There was a linear correlation between mast cell degranulation rate and PWL with 0. 737 in coefficient (P < 0.001). CONCLUSION: Single 650 nm laser and combined 650 nm + 10.6 microm laser with low intensity irradiated at "Zusanli" (ST 36) in acute adjuvant rats can provide remarkable analgesic effects, and there was a positive correlation between mast cell degranulation rate and analgesic effects, which plays an important part in laser irradiation-induced analgesia.

Profiling the response of human hair follicles to ultraviolet radiation.

Excessive UVR ranks among the most harmful environmental influences on human skin. However, the direct impact of UVR on human skin appendages remains to be systematically investigated. Organ-cultured human anagen hair follicles in vitro were irradiated, and reduction of hair shaft elongation, premature catagen entry, and reduced hair matrix keratinocyte proliferation were observed upon irradiation with UVB (20/50 mJ cm(-2)). At 20 mJ cm(-2), apoptotic cell death prevailed (casp-3/p53 activation), whereas at 50 mJ cm(-2), necrotic cell death was predominant (lactate dehydrogenase increase). Mitochondrial common deletion and oxidatively damaged genomic DNA (8-OH-dG) was mainly observed at 20 mJ cm(-2). Follicular melanogenesis and ACTH immunoreactivity drastically declined, but alpha-melanocyte-stimulating hormone remained unchanged, whereas transforming growth factor-beta(2) expression shifted from the outer toward the inner root sheath. Both the number of Giemsa+ mast cells and the degree of mast-cell degranulation increased in the connective tissue sheath (CTS), and CD117 immunoreactivity of CTS cells and matrix keratinocytes was upregulated. Thus, UVR differentially modifies hair growth and cycle, promotes cell death, and induces complex regulatory events in human hair follicles in vitro. The leads from this human organ model, which is a living and human tissue interaction system under physiologically relevant in situ conditions, may encourage its use for general investigation of UV-induced effects as well as for testing possible agents for their UV-protective potency.

Effect of low-intensity laser therapy on mast cell degranulation in human oral mucosa.

Little is known about the physiological mechanisms related to low-intensity laser therapy (LILT), particularly in acute inflammation and subsequent wound healing. The objective of this study was to verify the effect of LILT on mast cell degranulation. Epulis fissuratum tissues from eight patients were used. One part of the lesion was irradiated with an AsGaAl laser (lambda = 670 nm, 8.0 J/cm(2), 5 mW, 4 min). The other part was not irradiated. Then, the specimens were immediately removed, fixed and examined by light microscopy. The number of mast cells was similar in laser-treated samples when compared with non-irradiated specimens. The degranulation indexes of the mast cells observed in the irradiated samples were significantly higher than those of controls (P < 0.05). LILT with the parameters used increased the number of degranulated mast cells in oral mucosa.

Effects of low-level laser therapy on mast cell number and degranulation in third-degree burns of rats.

Mast cells have been shown to participate in the wound healing process. We investigated the effects of low-level laser therapy (LLLT) on mast cell number in the inflammation, proliferation, and remodeling phases of the wound healing process of experimental burns. Sixty rats subjected to third-degree burns were divided into four groups: two laser-treated, one control, and one nitrofurazone-treated group. In the two laser-treated groups, burned areas received LLLT with a helium-neon laser at energy densities of 38.2 J/cm(2) and 76.4 J/cm(2), respectively. The effects on mast cell number and degranulation were assessed 7, 16, and 30 days postburn (inflammation, proliferation, and remodeling phases of wound healing, respectively). Intact and degranulated mast cells were counted. Five rats with no burns were used for baseline studies. On day 7 in the first laser group, the total number of mast cells was significantly higher than in the other groups. On day 16 in the nitrofurazone-treated group, the total number of mast cells was significantly higher than in the control, first laser, and normal groups. LLLT on the experimental third-degree burns significantly increased the total number of mast cells during the inflammation phase of wound healing; also, topical application of 0.2% nitrofurazone ointment on the same burns significantly increased the total number of mast cells during the proliferation phase of burn healing.

[Effect of vector potential variations on monocyte/macrophage system parameters in mice in laboratory conditions].

The effect of 30-min vector potential variation on the phagocytosis of macrophages from laboratory mice was investigated. It was found that the effect changes the characteristics of mice immunity: the quantity and percentage of neutrophils and lymphocytes in the blood, the activity of capture, degranulation, the splitting of bacterial agents, and the dynamics of formation of reactive oxygen species.

Effects of gamma radiation on FcepsilonRI and TLR-mediated mast cell activation.

Ionizing gamma radiation has several therapeutic indications including bone marrow transplantation and tumor ablation. Among immune cells, susceptibility of lymphocytes to gamma radiation is well known. However, there is little information on the effects of gamma radiation on mast cells, which are important in both innate and acquired immunity. Previous studies have suggested that mast cells may release histamine in response to high doses of gamma radiation, whereas other reports suggest that mast cells are relatively radioresistant. No strong link has been established between gamma radiation and its effect on mast cell survival and activation. We examined both human and murine mast cell survival and activation, including mechanisms related to innate and acquired immune responses following gamma radiation. Data revealed that human and murine mast cells were resistant to gamma radiation-induced cytotoxicity and, importantly, that irradiation did not directly induce beta-hexosaminidase release. Instead, a transient attenuation of IgE-mediated beta-hexosaminidase release and cytokine production was observed which appeared to be the result of reactive oxygen species formation after irradiation. Mast cells retained the ability to phagocytose Escherichia coli particles and respond to TLR ligands as measured by cytokine production after irradiation. In vivo, there was no decrease in mast cell numbers in skin of irradiated mice. Additionally, mast cells retained the ability to respond to Ag in vivo as measured by passive cutaneous anaphylaxis in mice after irradiation. Mast cells are thus resistant to the cytotoxic effects and alterations in function after irradiation and, despite a transient inhibition, ultimately respond to innate and acquired immune activation signals.