Th2 cells and the ifn-γ R1 subunit in early and advanced experimental periodontitis in rats; an immunohistochemical study

ABSTRACT

Aim: To evaluate the involvement of Th2 cells in different periods of the active phase of experimental periodontal disease and expression of the R1 subunit of the receptor for IFN-γ during the early and advanced progression of the disease. Methods: Experimental periodontitis was induced in 30 male Wistar rats by placing cotton ligatures around the mandibular first molars. The rats were then randomly assigned into two groups G1=15 and G2=15, in group G1, ligatures were maintained for 2 days, a period that corresponds to the initial stage of periodontal disease in rats, in G2 ligatures were left for 15 days, a period that corresponds to the advanced stage of periodontal disease. The contra-lateral teeth served as controls (unligated). An immunohistochemical investigation of the gingival tissue was performed to detect the presence of the Th2 specific transcription factor (GATA3). Results Light microscopy analysis revealed a decreased expression of GATA-3-positive cells when bone loss progressed. IFN-γ R1 was detected at an early stage during the active phase of disease, but the expression of positive cells remained unaltered during the remaining period of the study.<Conclusions: These results indicate that the Th2 response may have a protective role during the pathogenesis of experimental periodontal disease, and that the IFN-γ R1 subunit may not be associated with periodontal disease progression.