A histopathologic study of the controlling role of T cells on experimental periodontitis in rats

Abstract

Background/purpose The onset and progression of periodontitis involve bacterial infection and the immune response. T cells function in the immune response and reportedly induce bone resorption in inflammatory bone loss. However, the exact role of T cells in periodontal destruction remains unclear. Using our experimental model of periodontitis, we aimed to investigate the influence of T cells on periodontal destruction. Materials and methods Male athymic nude (Nu) and euthymic wild-type (WT) rats were divided into the immunized (I-Nu and I-WT), non-immunized (nI-Nu and nI-WT). The immunized groups were immunized intraperitoneally with lipopolysaccharide (LPS). The non-immunized groups received phosphate-buffered saline (PBS). Nothing was administered to the non-treated groups. LPS was applied to the right palatal gingival sulcus in the immunized and non-immunized groups daily for 20 days. Loss of attachment, numbers of inflammatory cells and osteoclasts, and levels of alveolar bone were investigated histopathologically and histometrically. Osteoclasts were stained with tartrate-resistant acid phosphatase. The numbers of IL-4-positive cells were evaluated immunohistologically. Results Loss of attachment, numbers of inflammatory cells, levels of alveolar bone, and the number of osteoclasts were significantly increased in the nI-WT group compared with the nI-Nu group. However, the parameters were significantly increased in the I-Nu group compared with the I-WT group. The number of IL-4-positive cells was greater in the I-WT group than in the I-Nu group. Conclusion T cells promote inflammation in non-immunized animals; however, they regulate these processes in immunized animals.

Necrotizing sialometaplasia – Case report

“… 1 The diagnosis of necrotizing sialometaplasia usually does not need immunohistochemical staining to identify the cell types or origin of the tumor cells. 2 , 3 , 4 , 5 However, if needed, the immunostaining may be performed, and the low immunoreactivity for Ki-67 antigen or p53 protein can rule out the diagnosis of a squamous cell carcinoma or a mucoepidermoid carcinoma. 1 …”

Current views on pathogenetic factors of periodontitis development and potential effects of ligand-associated activation of vitamin D receptors: literature review

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