Effect of ethanol on lipid metabolism and epithelial permeability barrier of skin and oral mucosa in the rat

Attached Oral Mucosal Wound Closure using Blue Glue - A Prospective Clinical Study

Introduction

Traditionally, sutures have been widely used to close intraoral wounds. Various alternatives have been developed amongst which newer tissue adhesives such as N-butyl-2-cyanoacrylate having accepted clinical properties are gaining popularity. The primary purpose of the present study is to evaluate the efficacy of N-butyl-2-cyanoacrylate for intraoral attached mucosal wound closure following alveoloplasty.

Materials and Methods

In this prospective split-mouth study, 25 patients requiring alveoloplasty in either maxillary or mandibular arch bilaterally with a total of 50 sites were divided into two equal groups, namely silk suture (Group 1) and cyanoacrylate (Group 2). Each patient was evaluated on the first, third, seventh, 14th and 21st post-operative days. Parameters evaluated were time taken to close incision and to achieve haemostasis, pain, oedema, post-operative wound healing, patient discomfort and possible complications.

Results

Time taken to close incision, time taken to achieve haemostasis, post-operative pain and oedema were found to be less in Group 2. Wound healing too was found to be better in Group 2. There was one case of adhesive peel off on the first post-operative day which was managed by reapplying the tissue adhesive. The incidence of wound dehiscence and wound infection was observed more in Group 1 on the third post-operative day. Suture breakage (16%) and adhesive dislodgement (8%) were reported on the seventh post-operative day.

Discussion

The use of cyanoacrylates' inherent benefits, such as improved wound seal off in attached mucosa, quick polymerisation and bacteriostatic characteristics can be beneficial when performing minor oral surgical procedures on elderly, young and mentally challenged patients.

Understanding Scarring in the Oral Mucosa

Significance: Skin inevitably heals with the formation of a fibrotic scar. Patients affected by skin scarring suffer from long-term psychological and physical burdens. Recent Advances: Since the discovery of fetal scarless skin-wound healing, research has hoped to identify and mimic scarless healing for adult skin. Oral mucosa healing in adults provides the closest example to fetal scarless healing. Injuries to the oral mucosa heal with very minimal scarring. Understanding the mechanisms through which this process occurs may bring us closer to achieving scarless healing in adults. Critical Issues: In this review, we summarize the current evidence that illustrates distinct mechanisms involved in oral mucosal healing. We discuss the role of the oral niche in contributing to wound repair. The intrinsic properties of immune cells, fibroblasts, and keratinocytes within the oral mucosa that support regenerative repair are provided. We highlight the contribution of cytokines, growth factors, and chemokine secretion in permitting a scarless mucosal environment. Furthermore, we discuss the role of stem cell-like progenitor populations in the mucosa that may contribute to wound healing. We also provide suggestions for future studies that are needed to achieve scarless healing in adults. Future Directions: Many characteristics of the oral mucosa have been shown to contribute to decreased scarring, but the specific mechanism(s) is unclear. Advancing our understanding of oral healing may yield therapeutic therapies that can be used to overcome dermal scarring.

Damage to Oral Mucosae Induced by Weekend Alcohol Consumption: The Role of Gender and Alcohol Concentration

The damage caused by chronic alcohol consumption is frequently reported, but the effects caused by weekend recreational consumption, which is much more frequent than even daily consumption, have not, to our knowledge, been reported. The metabolism of ethanol, once consumed, starts from the mouth, and the biotransformation process follows different routes. In this study, the effect of weekend alcohol consumption on the oral cavity was observed. Methods: Thirty male and female rats were divided into six groups (n = 5), with control groups (male/female) and groups administered with 5% and 40% ethanol solution ad libitum consumption 2 days a week for 3 months. After treatment, the animals were sacrificed, an incisional slice of the cheek and back of the tongue was obtained, and the tissues were processed according to the histological technique and routine staining (hematoxylin-eosin, H&E). Samples were observed using light microscopy. Results: Histological changes were observed in samples of tongue and cheek mucosa including different levels of keratinization of the surface layer. Epithelial dysplasia, acanthosis, and chronic inflammation were also observed. The vascularization level also increased because of the ethanol-induced damage. The results were very similar between female and male groups. Conclusion: Weekend alcohol consumption for a period of 3 months causes oral-cavity tissue alterations that could contribute to tumor growth and the development of cancer in the oral cavity.

Zinc Prevents Ethanol-Induced Oxidative Damage in Lingual Tissues of Rats

The current study was designed to investigate the effects of zinc sulfate on cell proliferation, metallothionein (MT) immunoreactivity and antioxidant system against acute ethanol-induced oxidative damage in tongue tissues of rats. Wistar albino male rats, 2.5 to 3.0 months, were divided into four groups: Group I (n = 8), intact control rats; group II (n = 8), control animals given only zinc sulfate (100 mg/kg/day, for 3 consecutive days); group III (n = 14), animals given 1 mL absolute ethanol; group IV (n = 11), animals given zinc sulfate and absolute ethanol at the same dose and time. Animals were sacrificed under anesthesia 2 h after ethanol administration or 4 h after the last zinc sulfate treatment. Ethanol administration caused a marked decrease in the number of MT immunopositive cells and the proliferating cells in the lingual epithelium. A statistically significant decline in reduced glutathione levels, catalase activity and superoxide dismutase activities was also observed, whereas a significant elevation of lipid peroxidation levels and lactate dehydrogenase activities was detected in the ethanol group. In contrast, these changes were reversed by administration of zinc sulfate to ethanol-treated rats. In conclusion, it shows that zinc sulfate has therapeutic effects on acute ethanol-induced oxidative damage in the tongue tissues of rats.

Oral wound healing models and emerging regenerative therapies

Following injury, the oral mucosa undergoes complex sequences of biological healing processes to restore homeostasis. While general similarities exist, there are marked differences in the genomics and kinetics of wound healing between the oral cavity and cutaneous epithelium. The lack of successful therapy for oral mucosal wounds has influenced clinicians to explore alternative treatments and potential autotherapies to enhance intraoral healing. The present in-depth review discusses current gold standards for oral mucosal wound healing and compares endogenous factors that dictate the quality of tissue remodeling. We conducted a review of the literature on in vivo oral wound healing models and emerging regenerative therapies published during the past twenty years. Studies were evaluated by injury models, therapy interventions, and outcome measures. The success of therapeutic approaches was assessed, and research outcomes were compared based on current hallmarks of oral wound healing. By leveraging therapeutic advancements, particularly within in cell-based biomaterials and immunoregulation, there is great potential for translational therapy in oral tissue regeneration.

Pilot Study of Laser Doppler Measurement of Flow Variability in the Microcirculation of the Palatal Mucosa

Background. Histopathological alterations can arise when the denture-supporting mucosa experiences microbial and mechanical stress through the denture base and diagnosis of these diseases usually follows microvascular changes. Microcirculation measurement could allow for detection of such dysfunction and aid in the early diagnosis of palatal mucosa pathologies. Materials and Methods. We tested the sensitivity of laser Doppler for measuring the microcirculation of the palatal mucosa, assessing the median raphe (MR), Schroeder area (SA), and retroincisive papilla (RP). A Doppler PeriFlux 5000 System, containing a laser diode, was used. 54 healthy participants were recruited. We compare the measurements of PU (perfusion unit) using ANOVA test. Results. The numerical values for palatal mucosa blood flow differed significantly among the anatomical areas (p = 0.0167). The mean value of Schroeder area was 92.6 (SD: 38.4) and was significantly higher than the retroincisive papilla (51.9) (SD: 20.2) (p < 0.05), which in turn was higher than that of median raphe (31.9) (SD: 24.2) (p < 0.0001). Conclusion. Schroeder area appeared to have the greatest sensitivity, and vascular flow variability among individuals was also greatest in this region. We suggest that analysis of blood stream modification with laser Doppler of the palatal mucosa can help to detect onset signs of pathological alterations.

Cytotoxicity and metabolic stress induced by acetaldehyde in human intestinal LS174T goblet-like cells

There is compelling evidence indicating that ethanol and its oxidative metabolite acetaldehyde can disrupt intestinal barrier function. Apart from the tight junctions, mucins secreted by goblet cells provide an effective barrier. Ethanol has been shown to induce goblet cell injury associated with alterations in mucin glycosylation. However, effects of its most injurious metabolite acetaldehyde remain largely unknown. This study aimed to assess short-term effects of acetaldehyde (0, 25, 50, 75, 100 μM) on functional characteristics of intestinal goblet-like cells (LS174T). Oxidative stress, mitochondrial function, ATP, and intramitochondrial calcium (Ca(2+)) were assessed by dichlorofluorescein, methyltetrazolium, and bioluminescence, MitoTracker green and rhod-2 double-labeling. Membrane integrity and apoptosis were evaluated by measuring lactate dehydrogenase (LDH), caspase 3/7, and cleavage of cytokeratin 18 (CK18). Expression of mucin 2 (MUC2) was determined by cell-based ELISA. Acetaldehyde significantly increased reactive oxygen species generation and decreased mitochondrial function compared with negative controls (P < 0.05). In addition, acetaldehyde dose-dependently decreased ATP levels and induced intramitochondrial Ca(2+) accumulation compared with negative controls (P < 0.05). Furthermore, acetaldehyde induced LDH release and increased caspase3/7 activity and percentage of cells expressing cleaved CK18 and increased MUC2 protein expression compared with negative controls (P < 0.0001). ATP depletion and LDH release could be largely prevented by the antioxidant N-acetylcysteine, suggesting a pivotal role for oxidative stress. Our data demonstrate that acetaldehyde has distinct oxidant-dependent metabolic and cytotoxic effects on LS174T cells that can lead to induction of cellular apoptosis. These effects may contribute to acetaldehyde-induced intestinal barrier dysfunction and subsequently to liver injury.

Ethanol metabolism and its effects on the intestinal epithelial barrier

Ethanol is widely consumed and is associated with an increasing global health burden. Several reviews have addressed the effects of ethanol and its oxidative metabolite, acetaldehyde, on the gastrointestinal (GI) tract, focusing on carcinogenic effects or alcoholic liver disease. However, both the oxidative and the nonoxidative metabolites of ethanol can affect the epithelial barrier of the small and large intestines, thereby contributing to GI and liver diseases. This review outlines the possible mechanisms of ethanol metabolism as well as the effects of ethanol and its metabolites on the intestinal barrier. Limited studies in humans and supporting in vitro data have indicated that ethanol as well as mainly acetaldehyde can increase small intestinal permeability. Limited evidence also points to increased colon permeability following exposure to ethanol or acetaldehyde. In vitro studies have provided several mechanisms for disruption of the epithelial barrier, including activation of different cell-signaling pathways, oxidative stress, and remodeling of the cytoskeleton. Modulation via intestinal microbiota, however, should also be considered. In conclusion, ethanol and its metabolites may act additively or even synergistically in vivo. Therefore, in vivo studies investigating the effects of ethanol and its byproducts on permeability of the small and large intestines are warranted.

Fat tissue histological study at indocyanine green-mediated photothermal/photodynamic treatment of the skin in vivo

Histological slices of skin samples with the subcutaneous adipose tissue after photothermal/photodynamic treatment are analyzed. In the case of subcutaneous indocyanine green injection and 808-nm diode laser exposure of the rat skin site in vivo, the greatest changes in tissue condition were observed. Processes were characterized by dystrophy, necrosis, and desquamation of the epithelial cells, swelling and necrosis of the connective tissue, and widespread necrosis of the subcutaneous adipose tissue. The obtained data are useful for safe layer-by-layer dosimetry of laser illumination of ICG-stained adipose tissue for treatment of obesity and cellulite.

Epidemiology of cancer from the oral cavity and oropharynx

The classification of sites in tumors of the oral cavity, oropharynx, pharynx, and hypopharynx varies in the literature. More than 90% of these tumors of the mucosal lining are classified as squamous cell carcinoma developed from premalignant lesions such as leukoplakia and erythroleukoplakia. These carcinomas are associated to environmental and lifestyle risk factors, among which tobacco and alcohol play a major role. In addition to tobacco smoking, tobacco chewing is another risk factor as well as chewing betel quid and areca nut in Asia. Certain strains of virus, such as the sexually transmitted human papilloma virus, also play a carcinogenetic role. The temporal trends in incidence of these tumors relate to environmental factors; there is an increase in tendency in countries without prevention and a decrease in countries having an active policy of prevention of alcohol and tobacco consumption. In contrast, an increased incidence occurs in the world at tumor sites related to human papilloma virus infection in relation to changes in sexual habits.

Effects of acute alcohol consumption and vitamin E co-treatment on oxidative stress parameters in rats tongue

The aim of this study was to evaluate the effects of acute alcohol consumption and vitamin E co-treatment upon oxidative stress parameters in rats tongue. Thirty-eight, Wistar rats were separated into five groups (alcohol, alcohol/vitamin E, control, Tween, vitamin E). Alcohol and alcohol vitamin E groups had the standard diet, and 40% alcohol on drinking water. Other groups were fed with the same standard diet and water ad libitum. Vitamin E was given by gavage to vitamin E and alcohol/vitamin E rats twice a week. Alcohol and control groups were subjected to saline gavage and Tween group to 5% Tween 80 solution, the vitamin E vehicle. At day 14, the animals were anesthetized and specimens were obtained from tongue. Lipid peroxidation (TBARS), protein oxidative damage, catalase (CAT) and superoxide dismutase (SOD) activities were quantified. Alcohol group decreased TBARS in relation to control group and alcohol vitamin-treated animals decreased TBARS when compared to Tween and vitamin E groups. SOD activity was lower and CAT activity was higher in animals treated with both alcohol and vitamin E. These results suggest that short-term alcohol consumption decreases lipid peroxidation levels. Alternatively, alcohol/vitamin E group increased CAT, showing the toxicity of this association.

Alcohol intake and oral cavity cancer risk among men in a prospective study in Kerala, India

OBJECTIVE

The aim of the study was to evaluate the role of alcohol drinking and patterns of consumption in oral cancer incidence and mortality in a cohort study using data from the Trivandrum Oral Cancer Screening Study, India.

METHODS

At baseline, the study participants completed a lifestyle questionnaire including items on frequency and duration of alcohol consumption. They were followed up for oral cancer incidence and mortality. Data from 32 347 subjects, of whom 134 eventually developed oral cancer, were analysed to estimate risk of oral cancer incidence and mortality according to drinking patterns, using a Cox regression model adjusted for age, religion, education, occupation, body mass index (BMI), standard of living index, chewing habits, smoking habits, and vegetable and fruit intake.

RESULTS

Current and past drinkers were each associated with significantly increased risk of developing oral cancer. The hazard ratio increased significantly by 49% (95% CI = 1-121%) among current drinkers and 90% (95% CI = 13-218%) among past drinkers. A significant dose-response relationship between intake frequency, duration and oral cancer risk (incidence and mortality) was observed.

CONCLUSIONS

As with other lifestyle factors, alcohol intake plays an important role in oral carcinogenesis in this population, and understanding this role is relevant to developing public health policies targeting at-risk population.

Safety evaluation of topical applications of ethanol on the skin and inside the oral cavity

Ethanol is widely used in all kinds of products with direct exposure to the human skin (e.g. medicinal products like hand disinfectants in occupational settings, cosmetics like hairsprays or mouthwashes, pharmaceutical preparations, and many household products). Contradictory evidence about the safety of such topical applications of the alcohol can be found in the scientific literature, yet an up-to-date risk assessment of ethanol application on the skin and inside the oral cavity is currently lacking.The first and foremost concerns of topical ethanol applications for public health are its carcinogenic effects, as there is unambiguous evidence for the carcinogenicity of ethanol orally consumed in the form of alcoholic beverages. So far there is a lack of evidence to associate topical ethanol use with an increased risk of skin cancer. Limited and conflicting epidemiological evidence is available on the link between the use of ethanol in the oral cavity in the form of mouthwashes or mouthrinses and oral cancer. Some studies pointed to an increased risk of oral cancer due to locally produced acetaldehyde, operating via a similar mechanism to that found after alcoholic beverage ingestion.In addition, topically applied ethanol acts as a skin penetration enhancer and may facilitate the transdermal absorption of xenobiotics (e.g. carcinogenic contaminants in cosmetic formulations). Ethanol use is associated with skin irritation or contact dermatitis, especially in humans with an aldehyde dehydrogenase (ALDH) deficiency.After regular application of ethanol on the skin (e.g. in the form of hand disinfectants) relatively low but measurable blood concentrations of ethanol and its metabolite acetaldehyde may occur, which are, however, below acute toxic levels. Only in children, especially through lacerated skin, can percutaneous toxicity occur.As there might be industry bias in many studies about the safety of topical ethanol applications, as well as a general lack of scientific research on the long-term effects, there is a requirement for independent studies on this topic. The research focus should be set on the chronic toxic effects of ethanol and acetaldehyde at the point of impact, with special regard to children and individuals with genetic deficiencies in ethanol metabolism.

The effects of alcohol abuse on pulmonary alveolar-capillary barrier function in humans

AIMS

Alcohol abuse is associated with the development of the acute respiratory distress syndrome, a disorder characterized by abnormal alveolar-capillary permeability. We hypothesized that individuals with a history of alcohol abuse would have clinical evidence of abnormal alveolar-capillary permeability even in the absence of symptoms. This could contribute to their propensity for the development of this disorder.

METHODS

Thirty-three subjects with a history of alcohol abuse, but no other medical problems, and 13 age- and smoking-matched controls inhaled (99m)Tc-DTPA (technetium-labeled diethylenetriamine penta-acetate; an isotope used to measure lung permeability) for a 3-min period, and washout of this isotope was measured for a 90-min period. The rate at which it was cleared from the lungs was assessed and compared between subjects and controls.

RESULTS

The half-life of (99m)Tc-DTPA in the lungs of subjects with alcohol abuse was significantly shorter than that observed in matched controls, even when correcting for the effects of concomitant tobacco use. When the half-life of the isotope for smoking alcohol-abusing subjects and smoking controls were compared separately, there was a trend for the alcohol-abusing subjects to have a shorter half-life of the isotope present in the lungs. This was also true when non-smokers were compared.

CONCLUSIONS

These observations provide further evidence that alcohol abuse affects the normal permeability of the alveolar-capillary barrier and thereby may contribute to the development of the acute respiratory distress syndrome in individuals with alcohol abuse.

Potential mechanisms by which a single drink of alcohol can increase transdermal absorption of topically applied chemicals

BACKGROUND

Both chronic and acute ethanol consumption increase transdermal penetration of topically applied xenobiotics. The mechanisms by which this enhancement occurs are unknown. We hypothesized that either the vasodilatory effects of ethanol or its ability to disrupt the lipid bilayer via lipid peroxidation, may be contributing to the increased transdermal absorption observed in alcohol consuming animals.

METHODS

Male Wistar rats were gavaged with 1.5, 3, 4.3, 6 or 10 g/kg ethanol or saline control or were treated with either the vasoconstrictor epinephrine or with the vasodilator prilocaine. Dermal blood flow, transepidermal water loss (TEWL), and skin moisture were non-invasively measured. Transdermal penetration was then determined for four xenobiotics (paraquat, dimethyl formamide (DMF), 2,4-dichlorophenoxyacetic acid (2,4-D) and N,N-diethyl-m-toluamide (DEET)). Lipid peroxidation was also determined by monitoring the formation of malondialdehyde.

RESULTS

Dermal blood flow increased by approximately 27% (p<0.05), TEWL increased 1.12+/-0.2-fold while skin lipid peroxidation increased 1.4-fold (p<0.05) 2h after gavage with 10 g/kg alcohol. Transdermal penetration of paraquat was increased by prilocaine (ER=2.1+/-0.4, p<0.05), but the absorption of DEET, 2,4-D and DMF were not influenced by greater blood flow. Reducing dermal blood flow with epinephrine did not cause any significant changes in transdermal penetration.

CONCLUSIONS

Vasodilation triggered by a single episode of ethanol ingestion is not responsible for the observed increase in transdermal absorption. Ethanol induced changes in lipid peroxidation and TEWL demonstrate that drinking alcohol induces transdermal absorption of xenobiotics.

Transdermal absorption of the herbicide 2,4-dichlorophenoxyacetic acid is enhanced by both ethanol consumption and sunscreen application

Xenobiotics absorption is a health concern and skin is a major exposure site for many of these chemicals. Both alcohol consumption and topical sunscreen application act as transdermal penetration enhancers for model xenobiotics. The effect of combining these two treatments on transdermal absorption of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) was therefore examined. Skin from rats ingesting low (1.5 g/kg) medium (4.3 g/kg) or high (6 g/kg) ethanol doses or saline control was treated with a commercially available sunscreen containing titanium dioxide and octyl methoxycinnimate and transdermal absorption of 2,4-D was monitored. Ethanol increased penetration by a factor of 1.9, 2.0 and 2.5 for animals treated with 1.5, 4.3 and 6 g/kg respectively, demonstrating an ethanol-induced dose response. Sunscreen application to skin from ethanol gavaged rats caused 2,4-D absorption above that induced by ethanol alone by an additional factor of 1.3, 2.1 and 2.9 for 1.5, 4.3 and 6 g/kg respectively. Comparing 2,4-D transdermal absorption after exposure to both ethanol and sunscreen with a theoretical value (sum of penetration after ethanol or sunscreen treatment) demonstrates that these two treatments enhance additively at the higher doses tested. Results of this study emphasize the importance of limiting excessive alcohol consumption in individuals with potential herbicide exposure rather than discouraging the use of sunscreens, since the consequences of UV-induced skin cancer are far more series than the risks that would be associated with observed increases in chemical exposure.

A Single Oral Dose of Ethanol Can Alter Transdermal Absorption of Topically Applied Chemicals in Rats

Topical ethanol is used as a dermal penetration enhancer in some commercial products. Previous studies have demonstrated that chronic ethanol consumption can also disrupt skin barrier function, leading to increased transdermal penetration. This observation becomes much more relevant if a single drinking episode induces similar changes. The purpose of this study was thus to examine the transdermal penetration of three model chemicals after acute ethanol consumption. Wistar rats were gavaged with either 10, 6, 4.3, 3, 1.5 g/kg ethanol or saline and allowed to recover for 2 or 24 h. Blood and skin ethanol levels were determined and in vitro penetration experiments performed. The herbicide paraquat, industrial solvent N,N-dimethylformamide (DMF), and insect repellent N,N-diethyl-m-toluamide (DEET) were used as is model chemicals. Absorption was determined and directly compared between ethanol- and saline-treated skin by calculating enhancement ratios. Blood ethanol levels range from 0.25 to 0.015% at 2 h with skin levels at 12-18% of blood values. Ethanol enhances the absorption of paraquat, DMF, and DEET in a dose-dependent fashion. Paraquat and DEET showed no appreciable reduction in enhancement between 2 and 24 h postgavage for the 10-g/kg dose, but DMF did. Enhancement ratios were higher at 24 h for 10 than for 6 g/kg animals, demonstrating a dose-response relationship for recovery time. These studies imply that increased absorption of topical chemical occurs after alcohol ingestion. Both acute and chronic ethanol consumption can compromise the dermal barrier.

DNA damage, apoptosis and cell cycle changes induced by fluoride in rat oral mucosal cells and hepatocytes

AIM: To study the effect of fluoride on oxidative stress, DNA damage and apoptosis as well as cell cycle of rat oral mucosal cells and hepatocytes.

METHODS: Ten male SD rats weighing 80~120 g were randomly divided into control group and fluoride group, 5 animals each group. The animals in fluoride group had free access to deionized water containing 150 mg/L sodium fluoride (NaF). The animals in control group were given distilled water. Four weeks later, the animals were killed. Reactive oxygen species (ROS) in oral mucosa and liver were measured by Fenton reaction, lipid peroxidation product, malondialdehyde (MDA), was detected by thiobarbituric acid (TBA) reaction, reduced glutathione (GSH) was assayed by dithionitrobenzoic acid (DTNB) reaction. DNA damage in oral mucosal cells and hepatocytes was determined by single cell gel (SCG) electrophoresis or comet assay. Apoptosis and cell cycle in oral mucosal cells and hepatocytes were detected by flow cytometry.

RESULTS: The contents of ROS and MDA in oral mucosa and liver tissue of fluoride group were significantly higher than those of control group (P < 0.01), but the level of GSH was markedly decreased (P < 0.01). The contents of ROS, MDA and GSH were (134.73 ± 12.63) U/mg protein, (1.48 ± 0.13) mmol/mg protein and (76.38 ± 6.71) mmol/mg protein in oral mucosa respectively, and (143.45 ±11.76) U/mg protein, (1.44 ± 0.12) mmol/mg protein and (78.83 ± 7.72) mmol/mg protein in liver tissue respectively. The DNA damage rate in fluoride group was 50.20% in oral mucosal cells and 44.80% in hepatocytes, higher than those in the control group (P < 0.01). The apoptosis rate in oral mucosal cells was (13.63 ± 1.81) % in fluoride group, and (12.76 ± 1.67) % in hepatocytes, higher than those in control group. Excess fluoride could differently lower the number of oral mucosal cells and hepatocytes at G₀/G₁ and S G₂/M phases (P < 0.05).

CONCLUSION: Excess fluoride can induce oxidative stress and DNA damage and lead to apoptosis and cell cycle change in rat oral mucosal cells and hepatocytes.

Orally administered ethanol: transepidermal pathways and effects on the human skin barrier

Ethanol intake is associated with a variety of skin diseases. The aim of the present study was (1) to identify the pathways of release of orally administered ethanol through the skin, and (2) to investigate the effects of a single oral dose of ethanol on the penetration of topically applied substances into the skin. Ethanol evaporation via the skin was measured using the new technique of ion mobility spectrometry (IMS). Transepidermal water loss (TEWL) and skin surface temperature were simultaneously measured before and after ethanol consumption. Measurements were performed on skin sites with different stratum corneum (SC) thickness, and density of follicles and sweat glands. These appendages were selectively sealed to investigate their participation in ethanol evaporation. The penetration of a topically applied UV filter substance was studied before and after ethanol consumption after removing the SC with adhesive tape. Ethanol evaporation was measured within 5 min of consumption, while the skin surface temperature remained nearly constant. The sealing of the appendages did not have a significant effect on ethanol evaporation. On the forehead, a higher TEWL value was measured than on the forearm. On both skin sites, an increase in TEWL was observed after ethanol ingestion. No influence of orally administered ethanol on the penetration of the topically applied UV filter substance was observed. The results indicate that ethanol evaporation occurs via the lipid layers without a significant effect on the penetration of the topically applied substance.

Effects of individual characteristics on healthy oral mucosa autofluorescence spectra

Autofluorescence spectroscopy is a tool for detecting tissue alterations in vivo. In a previous study, we found spectral differences between clinically normal mucosa of different patient groups. These are possibly caused by associated patient characteristics. In the present study, we explore the influences of volunteer characteristics on healthy oral mucosa autofluorescence. Autofluorescence spectra were recorded in 96 volunteers with no clinically observable oral lesions. We applied principal components analysis to extract the relevant information. We used multivariate linear regression techniques to estimate the effect of volunteer characteristics on principal component scores. Statistically significant differences were found for all factors but age. Skin color strongly affected autofluorescence intensity. Gender differences were found in blood absorption. Alcohol consumption was associated with porphyrin-like peaks. However, all differences but those associated with skin color were of the same order of magnitude as standard deviations within categories. The effects of volunteer characteristics on autofluorescence spectra of the oral mucosa are measurable. Only the effects of skin color were large. Therefore, in lesion classification, skin color should be taken into account.

Effects of chronic alcohol consumption on dermal penetration of pesticides in rats

Topically applied ethanol is a well-known dermal penetration enhancer. The purpose of this work was to determine if ethanol consumption might also increase transdermal penetration. Male rats were fed either an ethanol containing or control diet for 6-8 wk. After the feeding regime was completed, skin was removed and placed in an in vitro diffusion system. The transdermal absorption of four very commonly used herbicides was determined. Penetration through skin from ethanol-fed rats was enhanced when compared to control by a factor of 5.3 for paraquat, 2.4 for atrazine, and 2.2 for 2,4-dichlorophenoxyacetic acid (2,4-D), and reduced by a factor 0.6 for trifluralin. Comparison of physical factors of the herbicides to the penetration enhancement revealed an inverse linear correlation with lipophilicity, as defined by log octanol/water partition coefficient (log Kow) with r2 =.98. These changes were at least partially reversible after 1 wk of abstinence from ethanol. These experiments demonstrate that regular ethanol consumption can alter the properties of the dermal barrier, leading to increased absorption of some chemicals through rat skin. If ethanol consumption has the same effect on human skin it could potentially have adverse health effects on people regularly exposed to agricultural, environmental, and industrial chemicals.