Comparative Morphological Study on Parotid and Submandibular Salivary Glands in Ovariectomized Rats / 치위생과학회지

Background@#Estrogen deficiency affects the structure and function of the salivary glands in women, leading to a decrease in salivary secretion and a change in the composition of saliva. Previous studies on changes in the salivary glands that cause estrogen deficiency have reported only partial results for the parotid and submandibular glands, and there are few comparative morphological studies of histological changes between the parotid and submandibular glands in ovariectomized rats (OVX) leading to estrogen deficiency. This study aimed to analyze the histopathological and histochemical changes in the parotid and submandibular salivary glands causing estrogen deficiency by using OVX, and to discuss the mechanism on these changes. @*Methods@#The parotid and submandibular glands from sacrificed control and OVX groups were fixed with cold 4% paraformaldehyde in phosphate buffer (pH 7.2). The tissues were dehydrated using a series of graded ethyl alcohol and embedded in paraffin. For histopathological analysis, sections cut to a thickness of 6 to 7 μm were stained with hematoxylin and eosin (H&E). For histochemical analysis, Periodic acid-Schiff (PAS), Alcian blue (AB, pH 2.5), and PAS+AB (pH 2.5 and pH 1) staining was performed. @*Results@#Histopathological analysis of OVX tissue showed that the parotid and submandibular salivary glands were broadly and clearly separated and divided into lobes. In OVX, acinar and ductal cells with condensed polymorphic or pyknotic nucleus, which are presumed to be characteristic of apoptotic cells, and degenerated cells with lipid deposition in cytoplasmic granules and ruptured membranes were increased. Histochemical analysis of OVX, confirmed an increase in the number and acidification of acinar secretory granules. @*Conclusion@#Histopathological and histochemical changes and the effects of estrogen deficiency are more evident in the submandibular salivary gland than in the parotid gland.

Effects of Calamansi Soju and Other Alcoholic Beverages on Resin Restorations / 치위생과학회지

Background@#The purpose of this study was to investigate the effects of commercially available calamansi soju and other alcoholic beverages on the microhardness and erosion of resin restorations. @*Methods@#In this study, we evaluated the effects of Calamansi soju, Chamisul fresh, Cass fresh, and Gancia Moscato D’asti on resin restorations. Jeju Samdasoo and Coca-Cola were used as negative and positive controls, respectively. Specimens to be immersed in the beverages were manufactured using composite resin according to the product instructions. In each group, the surface microhardness was measured using a surface microhardness instrument before and after immersion for 5, 15, 30, and 60 minutes. The pattern of change in the surface of the composite resin was observed under a scanning electron microscope (SEM). Paired t-tests, one-way ANOVA, and repeated measures ANOVA were performed to compare the surface microhardness of the specimens, and the Tukey test was used as a post hoc test. @*Results@#The pH of all beverages except Jeju Samdasoo was ＜5.5, which is the critical pH that can induce erosion. The difference in surface microhardness of the composite resin before and after immersion for 60 minutes was significant in all groups. In particular, the largest change in surface microhardness was observed in the calamansi soju group. In the SEM analysis, loss of composite resin was observed in all groups except the Jeju Samdasoo group, and rough surfaces with pores of various sizes were observed. @*Conclusion@#In this study, all beverages except Jeju Samdasoo decreased the microhardness of the composite resin surface, and it was confirmed that calamansi soju had the greatest change.

Inhibitory Effects on Oral Microbial Activity and Production of Lipopolysaccharides-Induced Pro-Inflammatory Mediators in Raw264.7 Macrophages of Ethanol Extract of Perilla flutescens (L.) Britton / 치위생과학회지

Background@#The leaves of Perilla frutescens, commonly called perilla and used for food in Korea, contain components with a variety of biological effects and potential therapeutic applications. The purpose of this study was to identify the components of 70% ethanol extracted Perilla frutescens (EEPF) and determine its inhibitory effects on oral microbial activity and production of nitric oxide (NO) and prostaglandin E2 (PGE2) in lipopolysaccharides (LPS)-stimulated Raw264.7 macrophages, consequently, to confirm the possibility of using EEPF as a functional component for improving the oral environment and preventing inflammation. @*Methods@#One kg of P. frutescens leaves was extracted with 70% ethanol and dried at −70o C. EEPF was analyzed using high-performance liquid chromatography analysis, and antimicrobial activity against oral microorganisms was revealed using the disk diffusion test. Cell viability was elucidated using a methylthiazolydiphenyl-tetrazolium bromide assay, and the effect of EEPF on LPS-induced morphological variation was confirmed through microscopic observation. The effect of EEPF on LPS-induced production of pro-inflammatory mediators, NO and PGE2 was confirmed by the NO assay and PGE2 enzyme-linked immunosorbent assay. @*Results@#The main component of EEPF was rosemarinic acid, and EEPF showed weak anti-bacterial and anti-fungal effects against microorganisms living in the oral cavity. EEPF did not show toxicity to Raw264.7 macrophages and had inhibitory effects on the morphological variations and production of pro-inflammatory mediators, NO and PGE2 in LPS-stimulated Raw264.7 macrophages. @*Conclusion@#EEPF can be used as a functional material for improving the oral environment through the control of oral microorganisms and for modulating inflammation by inhibiting the production of inflammatory mediators.

Anti-Oral Microbial Activity and Anti-Inflammatory Effects of Rosmarinic Acid in Lipopolysaccharide-Stimulated MC3T3-E1 Osteoblastic Cells on a Titanium Surface / 치위생과학회지

Background@#The purpose of this study was to investigate the anti-oral microbial activity and anti-inflammatory effects of rosmarinic acid (RA) in lipopolysaccharide (LPS)-stimulated MC3T3-E1 osteoblastic cells on a titanium (Ti) surface during osseointegration, and to confirm the possibility of using RA as a safe natural substance for the control of peri-implantitis (PI) in Ti-based dental implants. @*Methods@#A disk diffusion test was conducted to confirm the antimicrobial activity of RA against oral microorganisms. In order to confirm the anti-inflammatory effects of RA, inflammatory conditions were induced with 100 ng/ml of LPS in MC3T3-E1 osteoblastic cells on the Ti surface treated with or without 14 mg/ml of RA. The production of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated MC3T3-E1 osteoblastic cells on the Ti surface was confirmed using an NO assay kit and PGE2 enzyme-linked immunosorbent assay kit. Reverse transcription polymerase chain reaction and western blot analysis were performed to confirm the expression of interleukin (IL)-1β and tumor necrosis factor (TNF)-α in total RNA and protein. @*Results@#RA showed weak antimicrobial effects against Streptococcus mutans and Escherichia coli, but no antimicrobial activity against the bacteria Aggregatibacter actinomycetemcomitans and the fungus Candida albicans. RA reduced the production of pro-inflammatory mediators, NO and PGE2, and proinflammatory cytokines, TNF-α and IL-1β, in LPS-stimulated MC3T3-E1 osteoblastic cells on the Ti surface at the protein and mRNA levels. @*Conclusion@#RA not only has anti-oral microbial activity, but also anti-inflammatory effects in LPS-stimulated MC3T3-E1 osteoblasts on the Ti surface, therefore, it can be used as a safe functional substance derived from plants for the prevention and control of PI for successful Ti-based implants.

Inflammatory Effect of Light-Emitting Diodes Curing Light Irradiation on Raw264.7 Macrophage / 치위생과학회지

BACKGROUND: The light-emitting diode (LED) curing light used is presumed to be safe. However, the scientific basis for this is unclear, and the safety of LED curing light is still controversial. The purpose of this study was to investigate the effect of LED curing light irradiation according to the conditions applied for the polymerization of composite resins in dental clinic on the cell viability and inflammatory response in Raw264.7 macrophages and to confirm the stability of LED curing light. METHODS: Cell viability and cell morphology of Raw264.7 macrophages treated with 100 ng/ml of lipopolysaccharide (LPS) or/and LED curing light with a wavelength of 440~490 nm for 20 seconds were confirmed by methylthiazolydiphenyl-tetrazolium bromide assay and microscopic observation. The production of nitric oxide (NO) and prostaglandin E2 (PGE2) was confirmed by NO assay and PGE2 enzyme-linked immunosorbent assay kit. Expression of interleukin (IL)-1β and tumor necrosis factor (TNF)-α in total RNA and protein was confirmed by reverse transcription polymerase chain reaction and Western blot analysis. RESULTS: The LED curing light did not affect the viability and morphology of normal Raw264.7 cells but affected the cell viability and induced cytotoxicity in the inflammation-induced Raw264.7 cells by LPS. The irradiation of the LED curing light did not progress to the inflammatory state in the inflammation-induced Raw264.7 macrophage. However, LED curing light irradiation in normal Raw264.7 cells induced an increase in NO and PGE2 production and mRNA and protein expression of IL-1β and TNF-α, indicating that it is possible to induce the inflammatory state. CONCLUSION: The irradiation of LED curing light in RAW264.7 macrophage may induce an excessive inflammatory reaction and damage oral tissues. Therefore, it is necessary to limit the long-term irradiation which is inappropriate when applying LED curing light in a dental clinic.

Biological Effects of Light-Emitting Diodes Curing Unit on MDPC-23 Cells and Lipopolysaccharide Stimulated MDPC-23 Cells / 치위생과학회지

BACKGROUND: Light-emitting diodes curing unit (LCU), which emit blue light, is used for polymerization of composite resins in many dentistry. Although the use of LCU for light-cured composite resin polymerization is considered safe, it is still controversial whether it can directly or indirectly have harmful biological influences on oral tissues. The aim of this study was to elucidate the biological effects of LCU in wavelengths ranging from 440 to 490 nm, on the cell viability and secretion of inflammatory cytokines in MDPC-23 odontoblastic cells and inflammatory-induced MDPC-23 cells by lipopolysaccharide (LPS). METHODS: The MTT assay and observation using microscope were performed on MDPC-23 cells to investigate the cell viability and cytotoxic effects on LCU irradiation. RESULTS: MDPC-23 cells and LPS stimulated MDPC-23 cells were found to have no effects on cell viability and cell morphology in the LCU irradiation. Nitric oxide (NO) and prostaglandin E2 which are the pro-inflammatory mediators, and interleukin-1β and tumor necrosis factor-α (TNF-α) which are the proinflammatory cytokines were significantly increased in MCPD-23 cells after LCU irradiation as time increased in comparison with the control. LCU irradiation has the potential to induce inflammation or biological damages in normal dental tissues, including MDPC-23 cells. CONCLUSION: Therefore, it is necessary to limit the use of LCU except for the appropriate dose and irradiation time. In addition, LCU irradiation of inflammatory-induced MDPC-23 cells by LPS was reduced the secretion of NO compared to the LPS alone treatment group and was significantly reduced the secretion of TNF-α in all the time groups. Therefore, LCU application in LPS stimulated MDPC-23 odontoblastic cells has a photodynamic therapy like effect as well as inflammation relief.

Effect of Commercial Effervescent Vitamin Tablets on Bovine Enamel / 치위생과학회지

BACKGROUND: In this study, four types of effervescent vitamins marketed in Korea were analyzed for their acidity and vitamin content. For this purpose, bovine teeth were immersed in vitamin, and surface microhardness and appearance were measured before and after immersion to evaluate tooth demineralization and erosion.METHODS: Bovine permanent incisors with sound surface enamel were cut to 5×5 mm size, embedded in acrylic resin, and polished using a polishing machine with Sic-paper. The prepared samples were analyzed for pH, vitamin content, and surface hardness before and after immersion using a surface microhardness meter. Demineralization of surface dental enamel was observed using a scanning electron microscope.RESULTS: The average pH of the four effervescent vitamins was less than 5.5; the pH of the positive control Oronamin C was the lowest at 2.76, while that of the negative control Samdasoo was the highest at 6.86. The vitamin content was highest in Berocca and lowest in the DM company Multivitamin. On surface microhardness analysis, surface hardness values of all enamel samples were found to be decreased significantly after 1 and 10 minutes of immersion (p<0.05). After 10 minutes of immersion, there was a significant difference in the decrease in hardness between the experimental groups (p<0.05). Scanning electron microscopy observation showed that dental enamel demineralization after 10 minutes of immersion was the most severe in Oronamin C except for Samdasoo, followed by DM company Multivitamin and VitaHEIM. Immersion in BeroNew and Berocca resulted in similar effects.CONCLUSION: There is a risk of tooth erosion due to decreased tooth surface microhardness when using the four types of effervescent vitamins and vitamin carbonated beverages with pH below 5.5. Therefore, high pH vitamin supplements are recommended to prevent tooth erosion.

Antimicrobial Effect of Acanthopanax sessiliflorum Fruit Extracts against Selected Oral Bacteria / 치위생과학회지

This study aimed to evaluate the antimicrobial effects of Acanthopanax sessiliflorum fruit (ASF; Ogaza) extracts on Streptococcus mutans and Streptococcus sobrinus, which are agents that cause dental caries, and on Streptococcus mitis and Streptococcus salivarius, the microbial flora of the oral cavity. The ASF extracts obtained using 70% ethanol were fractionated in the order of ethyl acetate and n-Butanol, concentrated under reduced pressure, and lyophilized to give powdery solvent extracts. The antimicrobial activity of ASF extracts from each solvent was examined using the disk diffusion method. As a result, only those extracts obtained using an ethyl acetate solvent showed antimicrobial activity. These extracts were selected, and the minimum inhibitory concentration was measured by disk diffusion method at various extract concentrations. Results showed a minimum inhibitory concentration of 32 mg/ml. The viable cell count was measured to confirm the minimum bactericidal concentration. Results showed a minimum bactericidal concentration of 64 mg/ml. In the cytotoxicity test using normal human dermal fibroblast cells, the absorbance value of the test group was similar to that of the control group at 0.64, 1.28, and 6.4 mg/ml. The bacteria and their colonies were examined using a scanning electron microscope. Boundaries between the antimicrobial activity region and non-antimicrobial activity region were observed around the paper disk, which was immersed in the extract with 32 mg/ml concentration. Bacterial colonization was not observed in the area with antimicrobial activity. This finding suggests that ASF extracts can inhibit the growth of some microorganisms in the oral cavity, in addition to the effects of these extracts known to date. In particular, ASF extracts may be used as a preparation for preventing dental caries by adding the extract to the toothpaste or oral mouthwash.

Effect of Ultra-Soft and Soft Toothbrushes on the Removal of Plaque and Tooth Abrasion / 치위생과학회지

To improve the oral health status of Korean people, it is necessary to encourage proper oral hygiene management habits, such as toothbrushing, through appropriate health promotion techniques. Therefore, the purpose of this study was to evaluate the removal of plaque and tooth abrasion using ultra-soft (filament 0.11~0.12 mm) and soft toothbrushes for toothbrushing. The plaque removal was performed using a dentiform and Arti-spray, and the Patient Hygiene Performance (PHP) index was calculated as the sum total score divided by the total number of surfaces. In the abrasivity experiment, according to the number of brushings, a micro Vickers hardness tester was used, and a sample in the range of 280~380 Vickers hardness number was selected. The number of toothbrushing stroke were 1,800 (2 months), 5,400 (6 months), 10,800 (12 months), and 21,600 (24 months). The tooth abrasion was measured using a scanning electron microscope. Statistical analysis was performed using IBM SPSS Statistics 22.0 and a p-value < 0.05 was considered significant. According to the results, there was no statistically significant difference in the degree of plaque removal between ultra-soft and soft toothbrushes. The difference in tooth abrasion between before and after toothbrushing was found to be greater with the soft toothbrushes than with the ultra-soft toothbrushes. Therefore, the ultra-soft toothbrush not only lowers tooth damage by reducing tooth abrasion, but also shows a similar ability to remove plaque as soft toothbrushes.

Comparing Chewable and Manual Toothbrushes for Reducing Dental Plaque: A Pilot Study / 치위생과학회지

This study aimed to compare the effectiveness of chewable toothbrush and manual toothbrush and provide basic data for recommendation of the chewable toothbrush in specific groups and situations. A total of 20 subjects participated in this study (rolling method, 10; non-rolling method, 10). After professional prophylaxis, participants used the manual toothbrush to brush their teeth for 3 minutes. After a 7-day wash-out period, participants used the chewable toothbrush according to the manufacturer's instructions. Pre- and post-plaque indexing of the teeth was performed. The dental plaque index was assessed using the Turesky Modification of the Quigley-Hein Plaque Index (TMQHPI) for amount of plaque and Silness-Löe Plaque Index (SLPI) for plaque thickness. The difference between pre- and post-dental plaque index was analyzed using a paired t-test and the Wilcoxon signed-rank test. The Mann-Whitney U test was also used to compare the dental plaque index reduction rates. The dental plaque index differed significantly between the chewable toothbrush and the manual toothbrush. The TMQHPI reduction rate was significantly different between the rolling and non-rolling method groups for the manual toothbrush but not the chewable toothbrush. The difference in SLPI reduction rate between the rolling and non-rolling method groups was significant for the manual toothbrush but not for the chewable toothbrush. Differences in the dental plaque index reduction rates between the chewable and manual toothbrushes were not significant in the non-rolling method group. The results of this study showed higher reduction rates in dental plaque with manual toothbrush use than with chewable toothbrush use. However, the non-rolling method group did not show statistically significant differences according to toothbrush type. The present study showed that a chewable toothbrush can be an alternative to a manual toothbrush for individuals who have difficulty using the generally recommended rolling method.

Effects of the Enamel Erosion Caused by Certain Antipyretic and Analgesic Medicines for Children / 치위생과학회지

This study was conducted to provide basic understanding regarding possible enamel erosion by three kinds of fist-aid antipyretic and analgesic medicines over a period of time, with comparison and analysis of the resulting deciduous teeth surface and microhardness changes. The analysis was performed using energy dispersive X-ray spectroscopy (EDX) and scanning electron microscope (SEM) to examine the surface erosion and changes. The Kruskal-Wallis test show differences in surface erosion and changes after 3, 5 and 8 days of treatment as well as before and after the treatment in each group. According to the results, there was no significant difference in the early deciduous teeth enamel surface microhardness (p>0.01). However there were signigicant changes after 3, 5, and 8 days (p0.05). In the surface observation with the SEM treatment with Children's Tylenol® tablet, which has the lowest pH, looked the roughest, followed by Brufen syrup for children and Children's Tylenol® suspension. Based on these results, it should be considered that antipyretic and analgesic medicines for children, which have lower pH values, may cause tooth erosion. Hence, it is necessary to give special attention to oral hygiene in young children or infants by brushing their teeth after such drugs are administered.

Occluding Effect of the Application of Fluoride Compounds and Desensitizers on Dentinal Tubules / 치위생과학회지

This study compared and analyzed the occluding effects of fluoride compounds and desensitizers, which are commonly used in dental clinics, on dentinal tubules. This study also evaluated the persistence of the active ingredients over time by performing toothbrushing with an electric toothbrush. Thirty-five molar teeth, which had been extracted within the past 3 months from healthy people without tooth decays, amalgam fillings, or dental crowns, were divided into 4 pieces each. Of these, 135 teeth pieces were used as study specimens. These specimens were divided into a control group, an untreated group, and 5 experimental groups (acidulated fluoride gel, fluoride varnish, Gluma, Super Seal, and SE-Bond). The specimens were then subjected to toothbrushing equivalent to 1 week (140 times), 2 weeks (280 times), and 4 weeks (560 times), and the occluding effects on dentinal tubules in 3 regions of each specimen were examined under a scanning electron microscope. The fluoride varnish treated group showed the highest degree of dentinal tubule occlusion effects during the first, second, and fourth weeks of toothbrushing, with the SE-Bond treated group showing the second highest degree and the Gluma treated group showing the lowest degree. After 4 weeks of toothbrushing, the Gluma treated group and the Super Seal treated group showed the lowest degrees of dentinal tubule occlusion effects. In summary, the fluoride varnish treated group and the SE-Bond treated group displayed higher occlusion effects even after 4 weeks of treatment than did the other experimental groups. Therefore, it is the authors' belief that fluoride varnish and SE-Bond are effective for treating dentinal hyperesthesia.

Differential Expression of System L Amino Acid Transporters in Wound Healing Process of Rat Skin / 체질인류학회지

The continuous growth and proliferation of cells are essential for the wound healing process, and the amino acid transporters plays an important role in the continuous growing and proliferating cells. Among the amino acid transport systems, the amino acid transport system L, which is a Na+/-independent neutral amino acid transport system, is a major route for providing living cells including tumor cells with neutral amino acids including several essential amino acids. In the present study, to elucidate the role of amino acid transport system L in the wound healing process, we investigated the expression pattern of LAT1 and LAT2 in the healing process after inflicting the wound on skin of rat. The expression of LAT1 was increased at 12 hours after inflicting the wound and was similar to the control group getting closer to 7 days. The expression of LAT2 was increased at 1 day and 3 days after inflicting the wound and was similar to the control group getting closer to 7 days. These results suggest that the LAT1 and LAT2 play important roles at the early stage and at the middle stage getting closer to normal skin in the wound healing process after inflicting the wound, respectively.

Expression and function of OD314, Apin protein during ameloblast differentiation and amelogenesis / 대한치과보존학회지

This study was aimed to elucidate the biological function of OD314 (Apin protein), which is related toameloblast differentiation and amelogenesis. Apin protein, calcifying epithelial odontogenic (pindborg) tumors (CEOTs)-associated amyloid, were isolated from CEOTs, and has similar nucleotide sequences to OD314. We examined expression of the OD314 mRNA using in-situ hybridization during tooth development in mice. Expression of OD314 and several enamel matrix proteins were examined in the cultured ameloblast cell line up to 28 days by reverse transcription-polymerase chain reaction (RT-PCR) amplification. After inactivation and over-expression of the OD314 gene in ameloblast cell lines using U6 vector-driven RNA interference and CMV-OD314 construct, RT-PCR were performed to evaluate the effect of the OD314 during amelogenesis. The results were as follows: 1. In in-situ hybridization, OD314 mRNAs were more strongly expressed in ameloblast than odontoblast. 2. When ameloblast cells were cultured in the differentiation and mineralization medium for 28 days, the tuftelin mRNA expression was maintained from the beginning to day 14, and then gradually decreased to day 28. The expressions of amelogenin and enamelin were gradually decreased according to the ameloblast differentiation. 3. Inactivation of OD314 by U6-OD314 siRNA construct down-regulated the expression of OD314, MMP-20, and tuftelin, whereas over-expression of OD314 by CMV-OD314 construct up-regulated the expression of OD314 and MMP-20 without change in tuftelin. These results suggest that OD314 is considered as an ameloblast-enriched gene and may play the important roles in ameloblast differentiation and mineralization.

Expression of OD314 during ameloblast differentiation and maturation / 대한치과보존학회지

Ameloblasts are responsible for the formation and maintenance of enamel which is an epithelially derived protective covering for teeth. Ameloblast differentiation is controlled by sequential epithelial-mesenchymal interactions. However, little is known about the differentiation and maturation mechanisms. OD314 was firstly identified from odontoblasts by subtraction between odontoblast/pulp cells and osteoblast/dental papilla cells, even though OD314 protein was also expressed in ameloblast during tooth formation. In this study, to better understand the biological function of OD314 during amelogenesis, we examined expression of the OD314 mRNA and protein in various stages of ameloblast differentiation using in-situ hybridization and immunohistochemistry. The results were as follows : 1. The ameloblast showed 4 main morphological and functional stages referred to as the presecretory, secretory, smooth-ended, and ruffle-ended. 2. OD314 mRNA was expressed in secretory ameloblast and increased according to the maturation of the cells. 3. OD314 protein was not expressed in presecretory ameloblast but expressed in secretory ameloblast and maturative ameloblast. OD314 protein was distributed in entire cytoplasm of secretory ameloblast. However, OD314 was localized at the proxiamal and distal portion of the cytoplasm of smooth-ended and ruffle-ended ameloblast. These results suggest that OD314 may play important roles in the ameloblast differentiation and maturation.

Role of OD314 During Odontoblast Differentiation / 체질인류학회지

Odontoblasts are responsible for the formation and maintenance of dentin which is a mineralized part in dentin-pulp complex of tooth. OD314 was obtained by subtractive hybridization between odontoblasts and osteoblast/dental papilla cells, and differentiatially expressed in the odontoblasts but not in osteoblasts and dental papilla cells. In this study, to better understand the biological function of new odontoblast-enriched gene, OD314, we examined expression of OD314 in cultured MDPC-23 cells and intracellular localization of OD314 protein. We also evaluate the effect of OD314 over-expression and inactivation on the cells by northern analysis. When MDPC-23 cells are cultured in the differentiation and mineralization medium for 28 days, OD314 mRNA expression was gradually increased from the beginning to day 21 and remained relatively high on day 28. Immunofluorescent staining of cultured MDPC-23 revealed localization of OD314 on the cytoplasm, especially near the nuclear membrane. However, a small amount of fluorescence was also observed in the nucleus. Inactivation of OD314 by RNA interference up-regulated the expression of DSPP, whereas over-expression of OD314 by CMV-OD314 plasmid down-regulated the expression of ON. These results suggest that OD314, a odontoblat-enriched gene, may play important roles in the odontoblast differentiation and dentin mineralization.

Morphological Differences of the Wound Healing in Secretory Leukocyte Protease Inhibitor Knockout Mice / 체질인류학회지

Secretory leukocyte protease inhibitor (SLPI) is a serine protease inhibitor with anti-microbial properties found in mucosal fluids. At the tissue level, the ability of this 12kDa protein is to counteract the excessive degradation of functional and structural proteins such as collagen and fibronectin. Impaired healing states are characterized by excessive proteolysis and often bacterial infection, leading to the hypothesis that SLPI may have a role in this process. To investigate the role of SLPI in skin how it contributes to tissue repair, we have generated mice null for the gene encoding SLPI (Slpi), which show impaired cutaneous wound healing with increased inflammation. For the purpose of this, we have performed wound experiment in skin tissue with morphometrical analyses, immunohistochemistry, and Rnase protection assay. From these analyses, the results were that delayed healing in KO mice wounds compared to that of WT, prolonged inflammatory phase and increased TGF-beta1 in KO wounds, and lower mechanical properties in KO wounds. Taken together, SLPI may play a cruical role in cutaneous wounds healing especially in matrix reorganization that suggests the development as a clinical drug for wound healing.

Inactivation of the OD314 Gene by RNA Interference in Preodontoblast Cell Lines / 체질인류학회지

Tooth development depends on reciprocal interactions between oral epithelium and ectomesenchyme. The ectomesenchyme-derived odontoblasts secrete several collagenous and non-collagenous proteins to form a unique extracellular matrix. OD314 was obtained by subtractive hybridization between odontoblasts and osteoblast/pulp cells, and differentially or predominantly expressed in odontoblasts of rat incisors compared to osteoblasts and pulp cells. However, little is known about the function of OD314 in odontoblast differentiation. In this study, to better understand the function of OD314, we inactivated the OD314 gene in mouse MDPC23 cells using U6 promoter-driven siRNA method. After the characterization of mineralized nodule formation and molecular expression of MDPC23 cell, Inactivation effects of the OD314 were evaluated by RT-PCR and western blot. 1. Mineralized nodule formation was observed after 14 days of culture in MDPC23 cells. 2. The OD314, OC and DSPP mRNA were highly expressed throughout the cultures, while the expression of ON decreased as the MDPC23 cells differentiated. 3. The OD314 protein was weakly expressed at 7 days of culture, but increased gradually as MDPC23 cells reached mineralization stage. 4. The inactivation of OD314 by RNA interference downregulated the expressions of OD314, DSPP, OC, and ON mRNA and OD314 protein in MDPC23 cells. These results suggest that OD314 may play a important role in mineralization process of odontoblast and also regulate odontoblast-related genes such as OC, ON, and DSPP.

Immunohistochemical localization of several protein changes in periodontal ligament during tooth eruption and interdental separation of rats / 대한치과교정학회지

In this study, we attempt to investigate the mechanisms by which PDL cells regulate osteoclast formation and also to know whether PDL retained their characteristic phenotype during tooth eruption and interdental separation. Rats were prepared at developmental days 21 (pre-root formation), 27 (root development), 34 (advanced root formation/ eruption) and at later times(adult rats). To induce severe resorption state of alveolar bone and tooth root, interdental separation with brass wire was performed between the lower first and second molars for 2 weeks in adult rats. Rat mandibles were demineralized and embedded in paraffin, and horizontal and frontal section were prepared for immunohistochemical analysis using PDL-specific protein 22 (PDLs22), receptor activator of NFKB ligand (RANKL) and osteoprotegerin (OPG) antibodies. 1. Root formation and eruption stage of tooth development. 1) PDLs22 immunolocalization was observed in tooth follicle/PDL cells and osteoblasts throught out the root formation and eruption stages of tooth development. 2) RANKL expression became stronger at eruption stage than root formation stage of tooth development. 3) Strong expression of OPG was detected in follice/PDL cells of root formation stage but it was decreased with tooth eruption. 2. Interdental separation between lower first and second molar. 1) Comparared to normal animal, multinucleated osteoclasts and odontoclasts were markedly induced in the alveolar bone and tooth root with PDL remodeling in hematoxylin-eosin section. 2) PDLs22 expression was decreased with interdental separation. 3) RANKL expression was increased with interdental separation in PDL fibroblasts, osteoblasts, odontoclasts and it lacunae, resorbing dentin, cementum and bone matrix. 4) OPG expression was slightly decreased in the PDL cells adjacent to the alveolar bone and root surface with interdental separation. These results suggested that during tooth eruption and tooth movement, RANKL and OPG in the periodontal tissues are important determinants regulating balanced alveolar bone and tooth root resorption. And it is also suggested that PDL cells retained their characteristic phenotype during tooth eruption and interdental separation except for the short period of PDL remodeling.

Expression and functional characterization of odontoblast-derived gene: OD314 / 대한치과보존학회지

Odontoblasts are responsible for the formation and maintenance of dentin. They are known to synthesize unique gene products including dentin sialophosphoprotein (DSPP). Another unique genes of the cells remain unclear. OD314 was isolated from the odontoblasts/pulp cells of rats and partially characterized as an odontoblast-enriched gene (Dey et al., 2001). This study aimed to elucidate the biological function of OD314, relating to odontoblast differentiation and dentinogenesis. After determining the open reading frame (ORF) of OD314 by transient transfection analysis using green fluorescent protein (GFP) expression vector, mRNA in-situ hybridization, immunohistochemistry, reverse transcription-polymerase chain reaction (RT-PCR) and western analysis were performed. The results were as follows: 1. In in-situ hybridization, OD314 mRNAs were expressed in odontoblasts of developing coronal and root pulp. 2. OD314 was a novel protein encoding 154 amino acids, and the protein was mainly expressed in cytoplasm by transient transfection analysis. 3. Mineralized nodules were associated with multilayer cell nodules in the culture of human dental pulp cells and first detected from day 21 using alizarin-red S staining. 4. In RT-PCR analysis, OD314, osteocalcin (OC) and DSPP strongly expressed throughout 28 days of culture. Whereas, osteonectin (ON) mRNA expression stayed low up to day 14, and then gradually decreased from day 21. 5. Western blots showed an approximately 17 kDa band. OD314 protein was expressed from the start of culture and then increased greatly from day 21. In conclusion, OD314 is considered as an odontoblast-enriched gene and may play important roles in odontoblast differentiation and dentin mineralization.