ObjectiveTo observe the dynamic expressions of interleukin-35 (IL-35) and foxhead box p3 (Foxp3) in experimental rats with periapical periodontitis, and to explore the role of IL-35 in periapical periodontitis.

MethodsForty SPF-grade SD rats were selected and randomly divided into 5 groups.The model of periapical periodontitis was established by pulpotomy of the unilateral mandibular first molar.One group was sacrificed at random on the 0, 7, 14, 21 and 28 d after operation, respectively.X-ray films were taken in the mandible to observe periapical changes.The periapical tissues of the mandibular first molars were collected and stained with hematoxylin-eosin(HE) to observe their histopathological changes.The expressions of IL-35 and Foxp3 mRNA in the periapical lesions were dynamically detected using real-time quantitative PCR (RT-qPCR).

ResultsX-ray and HE staining showed that with the extension of pulp exposure time, the degree of periapical periodontitis increased gradually, and the inflammation tended to be stable after the pulp cavity was opened for 21 to 28 days.The clinical manifestations and histopathology confirmed the successful establishment of the periapical periodontitis.RT-qPCR results showed that the mRNA relative expression levels of IL-35 and Foxp3 increased in a fluctuating trend at different periods of operation (P < 0.01), increased rapidly at 0-7 days after pulp opening, decreased at 7-21 days (P < 0.05), and increased at 21-28 days (P < 0.05).Pearson correlation analysis showed that there was a positive correlation between IL-35 mRNA and Foxp3 mRNA expression (r=0.609, P < 0.05).

ConclusionsThe expression level of IL-35 in periapical periodontitis is inversely proportional to the degree of inflammation, which may be involved in the occurrence and development of periapical periodontitis by regulating the expression of Treg.