Correlation between Transforming Growth Factor-β and Periapical Lesions in Patients with Chronic Apical Periodontitis

Abstract

Objective. To examine the expression of transforming growth factor-β (TGF-β) in the periapical granulation tissue and serum of patients with chronic apical periodontitis and to conduct immunohistochemical analysis so as to explore the relationship between TGF-β and the degree of periapical lesions. Methods. Periapical granulation tissues of 20 cases of chronic apical periodontitis were collected as the experimental group. Healthy gingival tissues without eruption of third molars of 5 cases were collected as the control group. Immunohistochemistry, enzyme-linked immunosorbent assay, and real-time PCR (RT-PCR) were utilized to determine the expression of TGF-β mRNA and protein, and the difference in the expression of TGF-β was compared between groups. In the experimental group, oral CBCT was taken to measure the periapical bone resorption area. Spearman’s correlation method was applied to analyze the correlation between TGF-β protein and gene expression levels and periapical bone resorption area. Results. Immunohistochemistry and enzyme-linked immunosorbent assay demonstrated that the expression of TGF-β protein in chronic apical periodontitis tissue and serum was higher than that in the controls $\left(P<0.05\right)$ . RT-PCR revealed that the expression of TGF-β mRNA was higher in chronic apical periodontitis tissue than that of the controls $\left(P<0.05\right)$ . Spearman’s correlation analysis showed that in the experimental group, the mRNA expression of TGF-β was positively correlated with the periapical bone resorption area $\left(P<0.01\right)$ , and the protein expression level was not correlated with the periapical bone resorption area $\left(P<0.05\right)$ . Conclusion. The increased expression of TGF-β in the periapical granulation tissue and serum of patients with chronic apical periodontitis has a certain correlation with the progression of periapical periodontitis. The correlation between TGF-β at the mRNA level and the degree of early stage disease as well as the high expression of TGF-β in inflammatory cells in immunohistochemistry have confirmed that TGF-β promotes bone resorption in early periapical periodontitis, and its mechanism of action deserves further investigation.