Biomedical subjects

T Okiji

Publications and source records attributed to T Okiji.

At least 19 recordsLinked to original sources

PubMed2004

Immunocompetent cells in the pulp of human deciduous teeth.

This immunohistological study sought to determine how the distribution and density of various immunocompetent cells change in the pulp of human deciduous teeth during the process of physiological root resorption. Forty-three extracted deciduous teeth at various stages of resorption were subjected to immunoperoxidase staining with the use of antibodies directed to HLA-DR, CD68, factor XIIIa and lymphocyte subsets. In intact deciduous teeth (group 0), all types of cells examined, except for CD20+ B lymphocytes, were detected. In teeth in which resorption was less than 1/3 of the root length (group 1), all types of cells showed a statistically significant increase compared with group 0 (P<0.05; Mann-Whitney's U-test). HLA-DR+, CD68+, and factor XIIIa+ cells with a dendritic profile kept their distribution in the periphery of the pulp, and oval and round, newly recruited macrophages accumulated in the central portion of the pulp and near the resorption sites. In teeth where resorption was 1/2 to 2/3 (group 2), all the cell types increased further. Aggregations of HLA-DR+, CD68+, and factor XIIIa+ cells were frequently seen in the central portion of the pulp, and T and B lymphocytes occasionally formed some clusters. Comparisons with group 1 revealed that the density of these cells, except for CD20+ cells, showed significant increases (P<0.05; Mann-Whitney's U-test). These results provided evidence showing that immunocompetent cells of deciduous tooth pulp increase with the progress of physiological root resorption, suggesting that immunocompetency of deciduous teeth is altered by this process.

Analysis of Variance↗

PubMed2001

Localization and density of myeloid leucocytes in the periodontal ligament of normal rat molars.

The phenotypic distribution and density of macrophage-associated antigen-expressing cells in the periodontal ligament (PDL) of normal rat mandibular first molars was evaluated by immunohistochemistry, and an attempt made to identify dendritic cells (DCs) by immunoelectron microscopy. Cells immunopositive to ED1 (a general macrophage marker) were widely distributed throughout the PDL and were most common around blood vessels. A small number of T lymphocytes and OX62 (anti-veiled cells and gammadelta T cells)-positive DC-like cells were also found. The relative density of cells immunopositive to ED9 (CD14), OX42 (CD11b), OX6 (anti-class II MHC molecules), ED2 (anti-tissue-resident macrophages), 8A2 (CD11c) and WT.1 (CD11a) varied in the mesial, distal and periapical regions of the distal root and the furcal region. This finding suggests that there are several subpopulations of ED1-positive cells which express various combinations of these markers. Immunoelectron microscopy revealed that a small, but distinct, subpopulation of ED1- and OX6-positive cells did have a DC-like ultrastructure, although the majority of these cells were identified as macrophages. The DC-like cells were characterized by poorly developed lysosomal structures and an absence of phagocytic vesicles. It was concluded that the normal rat PDL is equipped with heterogeneous populations of macrophages with regional variations in density. The DC-like cells may function as antigen-presenting cells.

Animals↗

PubMed2001

An immunoelectron-microscopic study of class II major histocompatibility complex molecule-expressing macrophages and dendritic cells in experimental rat periapical lesions.

Previous studies have demonstrated that heterogeneous populations of class II major histocompatibility complex (MHC) molecule-expressing non-lymphoid cells, ultrastructurally classified as macrophages and dendritic cell (DC) cell-like cells, comprise the major immune cell population in experimental periapical lesions in rat molars. In this study, the temporal changes in relative proportions of the two types of cells were examined, on the hypothesis that they are involved in different aspects of the pathogenesis of the lesions. The lesions were induced by making surgical pulp exposures in mandibular first molars of 5-week-old Wistar rats. Observation periods were set at 0 (normal), 3, 14, 28, and 56 days. Non-lymphoid cells immunoreactive to OX6 (reactive to class II MHC molecules) were classified as macrophages and DC cell-like cells according to their ultrastructure, and the frequencies of the two types of cells were assessed at each time-point. ED1 (reactive to nearly all macrophages and DCs) was also used to identify macrophages and DC cell-like cells. At 3 days, most OX6+ cells and ED1+ cells in the periapical tissue had the ultrastructural appearance of newly recruited macrophages. At 14 days, when the lesion was actively expanding, there were significantly more OX6+ macrophages than OX6+ DC cell-like cells (P<0.01). However, at 28 days, when lesion expansion had ceased, DC cell-like cells significantly outnumbered OX6+ macrophages (P<0.01); this remained constant at 56 days. Cell-to-cell contact between OX6+ non-lymphoid cells and OX6- lymphocytes, suggesting a functional interaction, was most frequently seen at 28 days. These results support the notion that class II MHC molecule-expressing macrophages play some part in the initial lesion expansion, and suggest that DC cell-like cells may primarily be involved in immune defence against perpetuated antigenic challenges following lesion stabilization.

Animals↗

PubMed2001

Ultrastructural analysis of MHC class II molecule-expressing cells in experimentally induced periapical lesions in the rat.

Periapical lesions were induced by making 28 days of unsealed pulp exposures in the lower first molars of Wistar rats. Major histocompatibility complex class II molecule-expressing cells were then demonstrated by means of immunoperoxidase staining using a monoclonal antibody OX6, and the ultrastructure of these cells was analyzed under electron microscopy. OX6+ cells were classified into two major populations, (i.e. macrophages and dendritic cell (DC)-like cells. DC-like cells had elongated cytoplasmic processes, contained a few lysosomal structures, lacked distinct phagosomes, and were the most predominant cell type in the established lesion. Some of lymphocytes and plasma cells also showed a positive immunoreactivity. Both OX6+ macrophages and DC-like cells often showed a cell-to-cell attachment with lymphocytes. These findings suggested that major histocompatibility complex class 11 molecule-expressing macrophages and DC-like cells may play a crucial role in periapical lesion development by acting as antigen-presenting cells to memory T lymphocytes.

Animals↗

PubMed2000

Response of Class II molecule-expressing cells and macrophages to cavity preparation and restoration with 4-META/MMA-TBB resin.

AIM: The aim was to test the hypothesis that the resin and bonding agent 4-META/MMA-TBB (4-META), has the potential to prevent transdentinal antigenic challenges. METHODOLOGY: Class I cavity preparation and immediate restoration with 4-META were made in the maxillary right first molars of 36 six-week-old Wistar rats. Contralateral teeth with an unrestored cavity served as positive control (cavity without 4-META) group. The maxillary first molars of 12 age-matched normal rats (total 24 teeth) were also examined as negative control (intact tooth group). At 3 or 28 days after cavity preparation, the teeth were subjected to immunoperoxidase staining using OX6 (anticlass II molecules) and ED1 (antimacrophages) as primary antibodies. RESULTS: A total of 10 teeth were not available for histological examination. In the teeth filled with 4-META at 3 days, the density of OX6+ and ED1+ cells in the coronal pulp was significantly higher than that in the intact tooth group. At 28 days, formation of sound reparative dentine was noted and the density of the immunocompetent cells was comparable to the intact teeth. In the teeth without 4-META at 3 days, pulpal abscess was observed in 14 out of 16 and the density of OX6+ and ED1+ cells was significantly increased (P < 0.001, paired t-test) compared with the 4-META group. Partial pulp necrosis had developed in the teeth without 4-META at 28 days. CONCLUSIONS: Restoration with 4-META significantly reduced transdentinal antigenic challenges. This property may have special implications for 4-META's capacity to protect the dentine/pulp complex.

Abscess↗

PubMed1999

Enhanced expression of activation-associated molecules on macrophages of heterogeneous populations in expanding periapical lesions in rat molars.

Exudative macrophages are the most prevalent inflammatory cells during the entire pathogenetic process in experimentally induced rat periapical lesions. To clarify the significance of macrophages in the pathogenesis of periapical lesions, the way in which the phenotype of ED1 (a general marker for mononuclear phagocytes)-positive cells is modulated in actively expanding lesions was investigated, by immunoperoxidase staining with a panel of antibodies that recognize several activation-associated molecules on macrophages. Periapical lesions were induced experimentally by exposing the pulp in the lower first molars of Wistar rats. Active lesion expansion with morphological diversification of ED1-positive cells occurred between 14 and 28 days after the injury. Double immunoperoxidase staining revealed that ED1-positive cells coexpressing class II molecules of the major histocompatibility complex (MHC) molecules, inducible nitric oxide synthase (iNOS) and/or CD11a increased during the period of active lesion expansion. Increases of endothelial cells expressing intracellular adhesion molecule-1 and CD25 (interleukin-2 receptor)-expressing lymphocytes were also seen during the same period. Moreover, there existed two particular subpopulations of ED1 + cells in the established lesion at 28 days: (1) ED1++/class II MHC - /iNOS+ cells, located around the periapical abscess, and (2) ED1+/class II MHC+/ iNOS- cells with slender or dendritic morphology, distributed predominantly in the outer portion of the lesion where T lymphocytes were abundant. The first cell type could be a macrophage with potent phagocytic and antimicrobial actions, and the second might possess sufficient antigen-presenting capacity to cause the activation of T lymphocytes. It was concluded that macrophages, when activated, may participate in triggering lesion expansion. Functionally distinct subpopulations of macrophages may occupy different sites within the lesion where they can most effectively exert their specific functions.

Alveolar Bone Loss↗

PubMed1999

Co-increase of nerve fibers and HLA-DR- and/or factor-XIIIa-expressing dendritic cells in dentinal caries-affected regions of the human dental pulp: an immunohistochemical study.

Neuro-immune interaction has been suggested to play some modulatory role in the immunodefense of the dentin/pulp complex. In this study, we performed a simultaneous immunohistochemical observation of neural elements and pulpal dendritic cells (PDCs) on human carious teeth, to obtain morphological evidence for neuro-immune interaction in response to dentinal tubule-derived carious stimuli. Human third molars bearing a pulp-exposure-free caries lesion were studied. Immunoperoxidase staining was performed with anti-HLA-DR, anti-coagulation factor XIIIa, and anti-CD14 as PDC markers, and anti-low-affinity nerve growth factor receptor (NGFR), anti-protein gene products 9.5, and anti-calcitonin gene-related peptide as nerve markers. The carious teeth usually exhibited localized accumulation of both PDCs and nerve fibers immunoreactive to each marker, in the para-odontoblastic region corresponding to the pulpal end of carious dentinal tubules. Semi-quantitative digital densitometry revealed that pixel numbers corresponding to factor-XIIIa- and NGFR-immunoreactivity were significantly higher in the carious regions than those in the non-carious regions of the same teeth as well as those in the corresponding regions of intact teeth. Classification of specimens with respect to caries depth showed that the co-increase was most apparent in teeth with superficial caries. The increase of PDCs was less pronounced in carious teeth with reparative dentin. These findings suggest that both pulpal nerves and PDCs respond promptly and actively to dentinal tubule-derived carious stimuli. The synchronized accumulation of the two structures suggests an increased opportunity for neuro-immune interaction that may be of significance in the modulation of pathological processes in the dental pulp.

Dendritic Cells↗

PubMed1998

Responses of macrophage-associated antigen-expressing cells in the dental pulp of rat molars to experimental tooth replantation.

Bacterial infection of the dental pulp is a major hindrance to successful pulp regeneration after tooth replantation. This study examined how macrophages and class II molecule-expressing cells of the pulp respond to tooth replantation, on the hypothesis that they contribute to the defence and repair of the traumatized pulp. Upper right first molars of 5-week-old male Wistar rats were replanted immediately after extraction; contralateral untreated teeth served as controls. Pulpal cells expressing macrophage-associated antigens were immunohistochemically demonstrated at 0 h (immediately after the replantation) to 84 days postoperatively using antirat monoclonal antibodies OX6 (anti-class II molecules), ED1 (pan-macrophage antibody, reactive also with dendritic cells) and ED2 (anti-resident macrophages). Between 3 and 7 days postoperatively, ED1+ and OX6+ cells, but not ED2+ cells, were concentrated in areas of degeneration formed in the coronal pulp, and frequently showed a marked accumulation along the pulp-dentine border of the cuspal area. Confocal laser scanning microscopy revealed that some of the OX6+ cells with a dendritic profile extended several cytoplasmic processes into the dentinal tubules communicating with the enamel-free area at the tip of the cusp. From 14-84 days, approx. two-thirds of specimens exhibited pulp-tissue regeneration with increasing formation of reparative dentine. Following the formation of sound reparative dentine, cells positive to each antibody were distributed more centrally in the pulp than in the controls, and thus did not show any accumulation along the pulp-dentine border. However, in the other specimens where a bone-like hard tissue had formed in the pulp chamber, many ED1+ and OX6+ cells were still concentrated in the remaining pulp tissue and showed a marked accumulation along the pulp dentine border. Few ED2+ cells were observed in these specimens. These findings suggest that, following tooth replantation, exudative macrophages are actively engaged in eliminating dentinal tubule-derived infectious stimuli and that class II molecule-expressing cells, most probably containing dendritic cells, are positioned strategically at the outermost portion of the injured pulp to monitor incoming antigens. The intensity of the pulpal defence reaction may be dependent on the status of hard-tissue formation, which influences the amount of incoming antigens.

Animals↗

PubMed1998

Immune defense mechanisms of the dental pulp.

Defense reactions of the dentin/pulp complex involve a variety of biological systems, in which the immune system plays a pivotal role. The knowledge of the organization and function of pulpal immunocompetent cells has been sparse, but in recent years a significant body of information of immune mechanisms in general has provided a footing for substantial new knowledge of the immune mechanisms of the dental pulp. The identification of pulpal dendritic cells (DCs) has generated research activities which have led to a concept of how an antigenic challenge may evoke a pulpal inflammatory response. Although DCs are not able to identify foreign antigens specifically, they provide necessary signals to activate T-lymphocytes which in turn will orchestrate other immunocompetent cells to mount the local immune defense of the dental pulp. The purpose of this review is to accent the organization and function of pulpal DCs and other tissue and cellular components and to provide a basis for how they may interact to instigate pulpal defense mechanisms.

Antigen-Presenting Cells↗

PubMed1997

Defense responses of dentin/pulp complex to experimentally induced caries in rat molars: an immunohistochemical study on kinetics of pulpal Ia antigen-expressing cells and macrophages.

Experimental caries was induced in rats that were inoculated orally with Streptococcus mutants and maintained on a cariogenic diet. During the caries process, kinetics of the pulpal la antigen-expressing cells and macrophages was monitored immunohistochemically and was correlated with caries depth and the status of reparative dentin formation. Initial pulpal response was characterized by a localized accumulation of la antigen-expressing cells beneath the dentinal tubules communicating with the superficial caries. This was followed by a caries-depth related increase of la antigen-expressing cells and macrophages in the coronal pulp. The accumulation of these cells under the dentin was most apparent when the caries had progressed into the reparative dentin. These findings suggest that the response of la antigen-expressing cells to carious irritants triggers the defense reactions of the pulp. The intensity of the defense reactions may be correlated with the permeability of carious dentin.

Animals↗

PubMed1997

Perivascular dendritic cells of the human dental pulp.

The morphological and phenotypical features of the class II molecule (HLA-DR) expressing cells in human dental pulps were compared with those of previously characterized perivascular dendritic cells in the dermis. We have further investigated how these pulpal cells are structurally related to the vascular system. Double-immunofluorescence staining revealed that a substantial portion of the pulpal HLA-DR expressing cells also expressed factor XIIIa, a marker for dendritic cells. The cells usually had a highly dendritic appearance and formed a reticular network in the pulpal connective tissue. The majority of cells also expressed macrophage-related antigens (CD14 and CD68). A small but distinct population of pulpal cells, representing approximately 13% of the class II molecule expressing cells, was devoid of a typical macrophage phenotype. This subpopulation of pulpal cells may be similar to dendritic cells present in the dermis. Confocal laser scanning microscopy showed that highly dendritic cells, found in close relation to the endothelium, had dendritic processes which were found to be in contact with the peripheral cell membrane of the endothelial cells. These cells formed a three-dimensional structure around the microvessel resembling a cellular conduit. We conclude that the human dental pulp is equipped with class II molecule-expressing perivascular dendritic cells composed of a heterogeneous cell population.

Antigens, CD↗

PubMed1997

Structural and functional association between substance P- and calcitonin gene-related peptide-immunoreactive nerves and accessory cells in the rat dental pulp.

Defense mechanisms of the dentin/pulp complex involve a variety of biological systems in which immunocompetent cells, the nervous system, and the vascular supply play important roles. In the present study, pulpal accessory cells were examined regarding (i) their structural relationship to nerves and (ii) how the functional capacities of these cells were affected by neuropeptides. Micro-anatomic association was investigated in the normal rat molar pulp with the use of double-immunofluorescence staining and dual-channel confocal laser scanning microscopy. Examinations of confocal laser scanning microscopic images from single focal planes revealed the presence of apparent contacts between thin, varicose nerve fibers and immunocompetent cells, indicating proximity between these two structures. The close associations were most frequently observed in the para-odontoblastic region of the coronal pulp, where more than 70% of class II antigen-expressing (OX6+) cells showed proximity to nerve fibers immunoreactive to calcitonin gene-related peptide. The corresponding figure for substance P was about 50%. ED2+ macrophages closely associated with nerves were less frequently observed. Functional studies conducted in vitro demonstrated that 10(-9) to 10(-7) mol/L of substance P significantly increased (p < 0.05), while 10(-7) to 10(-6) mol/L of calcitonin gene-related peptide suppressed (p < 0.01) proliferation of purified T-lymphocytes stimulated with sub-optimal concentrations of concanavalin A in the presence of rat incisor pulpal cells as accessory cells. These data suggest that pulpal sensory nerve fibers and their products may have an influence upon the immune defense of the dental pulp.

Animals↗

PubMed1996

Age-related changes in the immunoreactivity of the monocyte/macrophage system in rat molar pulp.

Defence reactions of the dental pulp potentially involve a variety of immunocompetent cells, particularly class II major histocompatibility complex (MHC)-expressing cells and macrophages. In order to examine how the immunodefence potential of the pulp changes as a function of age, phenotypic distribution of pulpal cells expressing immunoreactivity to monoclonal antibody ED1 (reactive with nearly all macrophages and dendritic cells) was examined immunohistochemically in the lower first molars of developing (new-born to 10-week-old), adult (14-24-week-old) and aged (1-1.5-yr-old) Wistar rats. During tooth development, increasing numbers of ED1+ cells in the pulp also expressed immunoreactivity to ED2 (reactive with a differentiation-related antigen present on resident macrophages). ED1+ and ED2+ cells were distributed throughout the pulp before the tooth formation was completed. OX6+ (class II MHC-expressing) cells started to increase in number shortly after the eruption of the tooth and the increase continued even after the tooth formation had been completed. In aged rats, the density of the pulpal ED1+ cells was maintained at a relatively high level, whereas a significant decrease in the density of OX6+ cells was observed. These results indicate that the density and composition of pulpal cells expressing macrophage-associated antigens vary with increasing age, which most probably is related to changes in the immunological defence potential of the pulp against infection.

Aging↗

PubMed1996

Kinetics of macrophages and lymphoid cells during the development of experimentally induced periapical lesions in rat molars: a quantitative immunohistochemical study.

Quantitative phenotypical analysis for macrophages and lymphoid cells was made on periapical lesions induced by making unsealed pulp exposures in rat molars. Exudative macrophages of diverse morphology were the most dominating immunocompetent cells during all experimental periods. They exhibited almost complete distribution through the periapical lesions by the onset of active lesion expansion, and their kinetics and morphology were considerably similar to Ia+ non-lymphoid cells. Lymphoid cells started to show a notable increase shortly before the onset of active lesion expansion. CD4+ lymphocytes dominated at first, whereas CD8+ lymphocytes and plasma cells were dominant when the lesion size was stabilized. These findings suggest that macrophages of heterogenous populations play essential roles in the lesion pathogenesis by acting, depending on their functional heterogeneity, as effector cells or as antigen-presenting cells that stimulate CD4+ lymphocytes to induce an immune response. Interactions between plasma cells and CD8+ lymphocytes may be related to lesion chronicity.

Animals↗

PubMed1994

Distribution of Ia antigen-expressing nonlymphoid cells in various stages of induced periapical lesions in rat molars.

Periapical lesions were experimentally produced in rat lower first molars by exposing the pulp to the oral environment for 1 to 56 days. Temporal changes in the number and distribution of la antigen-expressing nonlymphoid cells in the periapical tissue were examined immunohistochemically on decalcified cryostat sections using OX6, a monoclonal antibody against rat la antigen. Influx of la-positive exudative cells into the periapical tissue was observed from 1 day postoperatively. Between 14 and 28 days when expansion of the periapical lesion was most evident, numerous la-positive macrophage-like and dendritic cell-like cells of diverse morphologies were found in the periapical tissue. The number of these cells showed further increase at 56 days postoperatively, when the lesion expansion had ceased. These results suggest the involvement of la antigen-expressing nonlymphoid cells in the development and perpetuation of periapical pathosis. They may act primarily as antigen-presenting cells, which are essential for the initiation of antigen-specific immune defense.

Animals↗

PubMed1993

Immunohistochemical detection of prostaglandin I2 synthase in various calcified tissue-forming cells in rat.

Localization of prostaglandin (PG) I2 synthase immunoreactivity was examined in demineralized sections of rat pulpal, periodontal and skeletal tissues using isn-1, a monoclonal antibody raised against the enzyme. Various calcified tissue-forming cells, i.e. odontoblasts, osteoblasts, osteocytes, cementoblasts, cementocytes and chondrocytes, were similarly immunoreactive for PGI2 synthase, suggesting that they are capable of producing PGI2. In odontoblasts and chondrocytes, the reactivity increased gradually with maturation. Weak immunoreactivity was also observed in endothelial cells and fibroblast-like cells in pulpal and periodontal tissues. However, no reactivity was seen in ameloblasts. These results suggest the possible involvement of PGI2 in the regulation of the metabolism of various calcified tissues. Monoclonal antibodies such as isn-1 may become useful markers of the maturation of calcified tissue-forming cells of mesenchymal origin.

Animals↗

PubMed1992

An immunohistochemical study of the distribution of immunocompetent cells, especially macrophages and Ia antigen-expressing cells of heterogeneous populations, in normal rat molar pulp.

The precise distribution of various immunocompetent cells in rat molar pulp was immunohistochemically examined by use of seven anti-rat monoclonal antibodies. It was demonstrated that rat molar pulp contained many OX6 (anti-Ia antigen)-positive cells and a large number of ED1 (anti-monocytes, macrophages, and dendritic cells)-positive, ED2 (anti-tissue macrophages)-positive, and/or OX35 (anti-macrophages and CD4+ lymphocytes)-positive cells. Macrophage-like cells predominated in the central portion of the pulp, while cells of dendritic appearance usually existed in the periphery of the pulp. Double-immunoperoxidase staining revealed that these cells showed some heterogeneity, but the majority could be classified as ED1+/OX6-/ED2+ cells, which may be Ia-histiocytes. Findings also suggested that true dendritic cells may be included in the ED1+/OX6+/ED2- category of cells. A small number of T lymphocytes and plasma cells were also detected. These results suggest that the normal dental pulp contains a variety of immunocompetent cells, with macrophages as the most dominating. Following the exogenous invasion of pathogenic stimuli in the pulp, these cells may participate in the defense reaction by acting as phagocytes or antigen-presenting cells, which are essential for the initiation of immune responses.

Animals↗

PubMed1992

Pathophysiological roles of arachidonic acid metabolites in rat dental pulp.

Arachidonic acid metabolism in normal rat incisor pulp was examined by measuring the conversion activity of exogenously added arachidonic acid in pulpal homogenates. It was demonstrated that the major metabolites were 12-hydroxyeicosatetraenoic acid and prostaglandin (PG) I2. Immunohistochemical studies revealed that PGI2 synthase was distributed in the pulpal blood-vessel cells, fibroblasts and odontoblasts, suggesting that PGI2 may contribute to regulating the function of these cells. When the incisor pulp was experimentally inflamed by applying lipopolysaccharide, arachidonic acid metabolism in the pulp showed overall increase. Change in the pulpal vascular permeability, which was assessed by quantifying the amount of extravasated dye, was almost parallel to the changes in PGE2 and PGI2 production. When production of the PGs was inhibited by indomethacin, the increase of vascular permeability in the inflamed pulp was also suppressed. Topically-applied PGE2 and PGI2 methyl ester abolished the suppression of increase in vascular permeability by indomethacin. These results suggest that PGE2 and PGI2 may be involved in the increase of vascular permeability in the experimental pulp inflammation. We further measured the production of leukotriene (LT) B4 in the inflamed pulp by incubating isolated pulp samples with Ca ionophore A23187, followed by radioimmunoassay. Change in LTB4 production was revealed to be almost parallel to that of neutrophil infiltration. BW755C, an inhibitor of both cyclooxygenase and lipoxygenase, reduced both LTB4 production and neutrophil infiltration. Accordingly, it was suggested that LTB4 may be involved in neutrophil infiltration in the experimental pulp inflammation.

Animals↗