Sung-Sam Lim

Tissue Levels of Matrix Metalloproteinases in Pulps and Periapical Lesions

The purpose of this study was to evaluate the tissue levels of matrix metalloproteinase (MMP)-1, -2, -3 and their distributions in inflamed human dental pulps and periapical lesions. Samples were subjected to enzyme-linked immunosorbent assay and/or immunohistochemistry by using specific antibodies to MMP-1, -2, and -3. Results from enzyme-linked immunosorbent assay were analyzed by using the Mann-Whitney U test and presented as p values. The concentrations of MMP-1 in all experimental groups were significantly higher than in the control (p < 0.05). The acute pulpitis and control groups were significant different in terms of their MMP-2 levels (p < 0.05). The concentration of MMP-3 in acute pulpitis was significantly higher than the control and chronic pulpitis groups (p < 0.05). Immunohistochemically, MMP-1 and MMP-3 were localized in the infiltrating neutrophils, macrophages, and extracellular matrix of the acute pulpitis group. These results suggest that MMPs play an important role in the pulp tissue destruction of acute, inflamed pulp.

Inhibition of inducible NO synthase, cyclooxygenase‐2 and interleukin‐1β by torilin is mediated by mitogen‐activated protein kinases in microglial BV2 cells

Background and purpose:  Traditionally, the stem and root bark of Ulmus davidiana var. japonica (Ulmaceae) have been known to be anti‐inflammatory in Korea. Anti‐inflammatory effects of torilin, isolated from this plant and the underlying mechanisms were examined by using lipopolysaccharide (LPS)‐stimulated microglial BV2 cells.

T Lymphocyte Subpopulations and Interleukin-2, Interferon-γ, and Interleukin-4 in Rat Pulpitis Experimentally Induced by Specific Bacteria

The objective of this study was to investigate the expression of surface markers on T lymphocytes and the Th1/Th2 immune response in pulpal inflammation associated with specific bacteria. Pulpal inflammation was experimentally induced in rat mandibular incisors by drilling, without coolant, to open pulp chambers. Streptococcus mutans (S. mutans group), Porphyromonas endodontalis (P. endodontalis group), and a sterile cotton pellet only (control group) were inoculated in the canal. The expression of CD25 and CD54 on CD4+, and CD8+ lymphocytes in pulp tissues was determined by using a flow cytometer. The levels of interleukin (IL)-2, interferon (IFN)-gamma, and IL-4 were measured by ELISA. Flow-cytometric analysis showed that the mean ratio of CD4+:CD8+ was 0.96 in the control group, 0.99 in the S. mutans group, and 0.52 in the P. endodontalis group. An increase in CD25 and CD54 expression on CD4+ T lymphocytes was related to the bacterial infection (p < 0.05) and accompanied an increase in IL-2 concentration. The higher concentration of IFN-gamma than IL-4 in the P. endodontalis group suggested a Th1 reaction in the early stage of pulpal inflammation induced by P. endodontalis.

Sonicated Extract of Enterococcus faecalis Induces Irreversible Cell Cycle Arrest in Phytohemagglutinin-Activated Human Lymphocytes

The purpose of this study was to examine whether the sonicated extract of Enterococcus faecalis (SEF) alters the cell cycle transition of lymphocytes and thus regulates the fate of the arrested cells. Human lymphocytes were activated by phytohemagglutinin in the presence or absence of SEF, and cell cycle was assessed by flow cytometry. Seventy-two hours after activation with phytohemagglutinin, cells were activated from G0/G1 to S (6.1%) and G2/M (3.8%) phases of the cell cycle. In contrast, pretreatment with SEF resulted in 90.5% of cells remaining in G0/G1, and cell cycle progression to the S and G2/M phases was consequently inhibited. Caspase assay demonstrated that SEF-treated cells exhibited significantly increased apoptosis (56.7%) compared with phytohemagglutinin alone (28.1%). We propose that if this irreversible cell cycle arrest induced by E. faecalis occurs in vivo, it may result in local immunosuppression and contribute to the pathogenesis of endodontic failure. Our findings that E. faecalis can inhibit lymphocyte responses may be of particular relevance to the pathogenesis of endodontic failure. Although the immunologic mechanism involved in the pathogenesis of persistent periapical lesion is not clearly defined, it is reasonable to predict that the altered immune reaction may be linked to the immunosuppressive potential of E. faecalis or other oral bacteria.

Oligonucleotide microarray analysis of apoptosis induced by 15‐methoxypinusolidic acid in microglial BV2 cells

Background and purpose:  We conducted a genome wide gene expression analysis to explore the biological aspects of 15‐methoxypinusolidic acid (15‐MPA) isolated from Biota orientalis and tried to confirm the suitability of 15‐MPA as a therapeutic candidate for CNS injuries focusing on microglia.

Effect of Sonicated Extracts of Enterococcus faecalis on the Production of Matrix Metalloproteinase-8 by Human Polymorphonuclear Neutrophils

This in vitro study monitored MMP-8 production on PMN by stimulated with the following three groups; Sonicated extracts of E. faecalis (SEF), SEF treated with Ca(OH)2 (12.5㎎/㎖) for 7 days, and lipopolysaccharides (LPS) of E. coli. The level of MMP-8 in each group was immediately measured by ELISA. The data were analyzed with Kruskal-Wallis test and Mann-Whitney U test. In the SEF group, the level of production of MMP-8 was higher than the negative control group in low concentration (0.05㎍/㎖) of SEF (p 0.05). All of the levels in E. coli LPS were increased with increasing concentrations (p < 0.05). According to this study we could summarize as follows: 1. MMP-8 was expressed at low level in untreated PMN group and the levels of MMP-8 were upregulated in PMN stimulated by E. coli LPS groups. 2. In the SEF groups, the level of production of MMP-8 decreased with an increase in the concentration of SEF (p < 0.05). So E. faecalis may have suppressive effect on the production of MMP-8 by PMN. 3. In the case of SEF treated with Ca(OH)2, all of the MMP levels at different SEF concentrations were higher than untreated PMN group (p < 0.05), but no statistical difference was found among the differ

Effects of Enterococcus faecalis sonicated extracts on IL-2, IL-4 and TGF-β1 production from human lymphocytes

In order to examine the immunoresponse of host cells to Enterococcus faecalis, this in vitro study monitored the production of Interleukin-2 (IL-2), Interleukin-4 (IL-4) and Transforming growth factor-β 1 (TGF-β 1) in human lymphocytes. Lymphocytes were activated with PHA in the presence or abscence of sonicated extracts of E. Faecalis (SEF) and further incubated for 72 hours. The level of each cytokine was measured by ELISA. Data were analyzed with Kruskal-Wallis test and MannWhitney U test (P < 0.05). PHA-activated group did exhibit higher level of IL-2 and IL-4 than untreated control group. The levels of expression of both cytokines were significantly decreased following the treatment of high (25 ㎍/㎖) and medium concentration (12.5 ㎍/㎖) of SEF (P <0 .05) than those of PHA activated group. But low concentration (5 ㎍/㎖) of SEF showed the similar level of IL-2 and IL-4 production as those of PHA activated group. TGF-β 1 was unaffected by SEF treatment. These results suggested that E. faecalis may suppress IL-2 and IL-4 production by lympho

Cytotoxicity and Antibacterial property of New Resin-based Sealer

The main objective of a successful endodontic treatment is the proper cleaning and shaping of the root canal, as well as a total obturation of the canal space with an inert, dimensionally stable and biologically compatible material. A large variety of root canal filling materials have been used through the years. To achieve an effective seal and promote healing, a root canal sealer should possess certain characteristics. Grossman identified several characteristics of the ideal sealer. One of these is that it must have bactericidal or bacteriostatic activity. Several antibacterial agents have been added to root canal sealers to improve this effect. In addition, it should be completely compatible with the periapical tissue, being neither toxic nor inflammatory. There have been many reports showing that resin-based sealers have better physical characteristics than zinc oxide-eugenol-based sealers, and that AH 26, in particular, which is composed mainly of epoxy resin, is quite effective because of its close adaptation to the root canal walls and its very low contraction rate during setting. As far as the cytotoxicity of resin-based sealers is concerned, there have been conflicting results. However, several researchers have reported that the cytotoxicity is quite strong at the time of mixing but weakens over time. Cytotoxicity and Antibacterial property of New Resin-based Sealer

The effect of Treponema denticola immunoinhibitory protein on cytokine expression in T cells

Immunoinhibitory protein extracted from sonicated Treponema denticola have been shown to suppress cell cycle progression of human lymphocytes. To study in detail about the effect of this microorganism on the function of lymphocytes. we investigated the levels of Interleukin-2 (IL-2) and Interleukin-4 (IL-4) production by T lymphocytes before and after the addition of T. denticola sonicated extracts. In this study. levels of IL-2 and IL-4 produced from T cells pretreated with sonicated extracts were evaluated by using the quantitative sandwich enzyme immunoassay technique. In response to phytohemagglutinin (PHA) stimulation. T cell produced increased levels of IL-2 and IL-4. However. the expressions of both cytokines were significantly inhibited when PHA activated-T cells were pre-exposed to sonicated T. denticola extracts (p

Interleukin-6 and Interleukin-10 in experimentally induced rat Pulpal inflammation

방 법 실험적으로 치수의 염증반응을 일으키기 위하여 치수염의 원인균으로 알려진 Prevotella nigrescens를 이용 하였다. 실험동물의 하악절치의 incisal tip부분을 절단한 후(n=120), 치수강을 개방시켰다. 실험군에서는 Prevotella nigrescens를 멸균된 면구에 묻혀서 개방된 치수강 내에 접종하였으며, 대조군에서는 균을 접종하 지 않고 멸균된 면구만을 개방된 치수강 내에 위치시켰다. 그 후 1, 2, 5일이 경과되었을 때 실험에 사용된 치아를 발치 하여, 치수조직을 적출하였다. Amersham사의 ELISA kit를 사용하여 적출된 치수조직내의 Interleukin-6와 Interleukin-10의 양을 측정하였으며 그 결과를 Mann-Whitney rank sum test를 사용하여 통계학적 유의성을 검증 하였다. 조직학적 검사를 위해서는 발치된 치아를 nitric acid를 사용하여 탈회시킨 후 헤마톡실린-에오신 염색을 시행 한 후 관찰하였다.