Expression Of Interleukin-35 In Rat Model Of Periapical Inflammation

Objective: To observe the dynamic expression between Interleukin-35(IL-35)of experimental apical periodontitis in rats and retinoid-related orphan nuclear receptorγt(RORγt),the specific transcription factor of T helper cell 17(Th17),and forkhead/winged helix transcription factor 3(Foxp3),the specific transcription factor of Regulatory T cell(Treg);to learn about the expression changes of IL-35 in the progression of apical periodontitis;and to further analyze the relationship of IL-35 to RORγt and Foxp3 to explore the possible mechanism of IL-35.Methods: Forty 8-week-old SPF SD rats weighing 220-300 g were randomly divided into 5 groups.The unilateral mandibular first molar was endodontically opened to establish the periapical periodontitis model.One group was randomly selected and sacrificed at 0,7,14,21 and 28 days after operation,respectively.The periodontal ligament space and periapical tissue density of the mandibular first molar in each group were observed.Hematoxylin-eosin staining and real-time fluorescent quantitative reverse transcription polymerase chain reaction were used to observe the pathological changes of the periapical tissue of the mandibular first molar.The expression of IL-35,RORγt and Foxp3 m RNA in the periapical lesion tissue of each group was detected.Result: X-ray and HE staining showed that the degree of apical inflammation gradually increased with the extension of pulp exposure time from 7 to 21 days,and tended to be stable from 21 to 28 days after the opening of the pulp cavity.The successful establishment of the rat model of periapical inflammation was confirmed by X-ray imaging and histopathology.RT-q PCR: The results of RT-q PCR showed that the expressions of IL-35,RORγt and Foxp3 m RNA were different with the increase of the days of open pulp,and the difference was statistically significant(P<0.05).The expressions of IL-35 and Foxp3 in the 7d,14 d,21d and 28 d groups were significantly higher than those in the 0d control group(P<0.05).The expression decreased with the aggravation of periapical inflammation from day 7 to day 21,and increased from day21 to day 28(P<0.05).The expression of RORγt increased gradually with the aggravation of periapical inflammation,and there was a downward trend at 28 d compared with 21d(P<0.05).Pearson correlation analysis showed that IL-35 was positively correlated with Foxp3(r=0.609,P<0.05)and negatively correlated with RORγt(r=-0.315,P<0.05).Conclusion:1.IL-35 is highly expressed in periapical periodontitis,which is inversely proportional to the degree of inflammation,suggesting that IL-35 may be involved in the progression of periapical periodontitis and play a protective role.2.IL-35 is positively correlated with Foxp3 and negatively correlated with RORγt in periapical periodontitis,suggesting that IL-35 is closely related to Th17 and Treg,which are characteristic transcription factors of RORγt and Foxp3,respectively.It may be involved in the progression of apical periodontitis by regulating the expression of Th17 and Treg.