Restorative Dentistry & Endodontics

Interplay of collagen and mast cells in periapical granulomas and periapical cysts: a comparative polarizing microscopic and immunohistochemical study: Deepty Bansal, Mala Kamboj, Anjali Narwal, Anju Devi, Nisha Marwah; Restor Dent Endod 2022;47(1):e12. Published online February 14, 2022; DOI: https://doi.org/10.5395/rde.2022.47.e12

Abstract PDF PubReader ePub: Objectives
This pilot study aimed to establish the interrelationship between collagen and mast cells in periapical granulomas and periapical cysts.
Materials and Methods
An observational cross-sectional study was conducted on the paraffin-embedded tissue sections of 68 specimens (34 periapical granulomas and 34 periapical cysts). The specimens were stained with picrosirius to observe collagen fiber birefringence and anti-tryptase antibody to evaluate the mast cell count immunohistochemically. The mean number and birefringence of collagen fibers, as well as the mean number of mast cells (total, granulated, and degranulated), and the mean inflammatory cell density were calculated. The data obtained were analyzed using the Kruskal Wallis test, Mann Whitney U test, and Spearman correlation test (p < 0.05).
Results
The mean number of thick collagen fibers was higher in periapical cysts, while that of thin fibers was higher in granulomas (p = 0.00). Cysts emitted orange-yellow to red birefringence, whereas periapical granulomas had predominantly green fibers (p = 0.00). The mean inflammatory cell density was comparable in all groups (p = 0.129). The number of total, degranulated, and granulated mast cells exhibited significant results (p = 0.00) in both groups. Thick cyst fibers showed significant inverse correlations with inflammation and degranulated mast cells (p = 0.041, 0.04 respectively).
Conclusions
Mast cells and inflammatory cells influenced the nature of collagen fiber formation and its birefringence. This finding may assist in the prediction of the nature, pathogenesis, and biological behavior of periapical lesions.

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The comparison of gene expression from human dental pulp cells and periodontal ligament cells: Hyoun So, Sang-Hyuk Park, Gi-Woon Choi; J Korean Acad Conserv Dent 2009;34(5):430-441. Published online September 30, 2009; DOI: https://doi.org/10.5395/JKACD.2009.34.5.430

The purpose of this study was to characterize functional distinction between human dental pulp cells(PC) and periodontal ligament cells(PDLC) using cDNA microarray assay and to confirm the results of the microarray assay using RT-PCR. 3 genes out of 51 genes which were found to be more expressed(>2 fold) in PC were selected, and 3 genes out of 19 genes which were found to be more expressed(>2 fold) in PDLC were selected for RT-PCR as well.

According to this study, the results were as follows:

1. From the microarray assay, 51 genes were more expressed (2 fold) from PC than PDLC.

2. RT-PCR confirmed that ITGA4 and TGF β2 were more expressed in PC than in PDLC.

3. From the microarray assay, 19 genes were more expressed (2 fold) from PDLC than PC.

4. RT-PCR confirmed that LUM, WISP1, and MMP1 were more expressed in PDLC than in PC.

From the present study, different expression of the genes between the PC and PDLC were characterized to show the genes which play an important role in dentinogenesis were more expressed from PC than PDLC, while the genes which were related with collagen synthesis were more expressed from PDLC than PC.

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The levels of interleukin-2, interferon-γ, interleukin-4 and T lymphocyte subpopulations in rat pulpal inflammation induced experimentally by specific bacteria: Seon-Ah Kim, Sung-Sam Lim; J Korean Acad Conserv Dent 2002;27(1):1-11. Published online January 31, 2002; DOI: https://doi.org/10.5395/JKACD.2002.27.1.001

Abstract PDF PubReader ePub

Immune responses associated with bacterial infection involve various inflammatory cells. Clinical symptoms and pathologic features are particularly influenced by the predominant cells. Among inflammatory cells, T cells have the heterogenity. T cells may develop into the mature cells expressing the cell surface markers with different functions and T helper cells are categorized into Th1 and Th2 cells based on their different patterns of cytokine production. The objective of this study was to investigate the change of expression of surface markers on T cells and the Th1/Th2 immune response in pulpal inflammation associated with specific bacteria.

We experimentally induced pulpal inflammation in rat incisors by drilling without coolant and innoculated with Streptococcus mutans (S.M. group), Porphyromonas endodontalis (P.E. group), or only sterile cotton (control group). After 1, 2, and 5 days, mandibular incisors were extracted and the pulp tissues were extirpated. The expressions of IL-2 recepters (CD25) and ICAM-1 (CD54) on CD4+ and CD8+ cells in the pulps were determined using a flow cytometer, and the concentration of IL-2, IFN-γ and IL-4 was measured by enzyme-linked immunosorbent assay.

The results were as follows;

1. In the S.M. group, CD4+ cells were more increased at 2nd day than 1st day and in the P.E. group, CD8+ cells were more increased at 2nd day than 1st day.

2. The percentages of CD4+, CD4+25+ and CD4+54+ cells were decreased in the pulp tissues at 5th day after irritation in all groups.

3. The ratios of CD4+/CD8+, CD4+/CD4+25+ and CD4+/CD4+54+ in the pulps at 2nd day after irritation by P. endodontalis were significantly lower than the other groups.

4. The higher concentrations of IFN-γ than IL-4 in the pulps at 2nd day after irritation by P. endodontalis showed that T helper 1 reaction were predominant in the early stage of the pulpal inflammation induced by P. endodontalis.

5. The higher concentrations of IL-4 than IFN-γ in the pulps at 1st day and 5th day after irritation by S. mutans were measured but the differences were not significant.

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