The Expression Of CD40 MRNA In Human Normal And Inflamed Pulp Tissue

Objective: CD40 and its ligand CD40 L are two transmembrane glycoproteins on the cell surface, the former is a member of the tumor necrosis factor receptor(TNFR) superfamily, and the latter is a member of the tumor necrosis factor(TNF) superfamily. The interaction of CD40-CD40 L plays an important role not only in humoral immunity, but also in cellular immunity. Previous studies have shown that the expression level of CD40 in inflammatory diseases is significantly elevated, and the interaction of CD40-CD40 L can increase the production of inflammatory mediators in a variety of inflammatory cells, and further promote the development of the irreversible inflammatory disease. As the pulp tissue is subject to bacterial infection or physical and chemical stimulation, pulpitis is a kind of complex inflammatory and immune responses to a variety of cytokines. For the great occurrence of pulpitis, the study of the mechanism is an important scientific subject. Whether CD40 participates the inflammation of dental pulp in the acute and chronic pulpitis through CD40-CD40 L interaction on the surface of cells is not clear.In our study, the expression of CD40 m RNA in the normal adults, acute and chronic dental pulp tissue were detected by the means of reverse transcription polymerase chain reaction(RT-PCR).And we tried to find the role of CD40 in the acute and chronic inflammation of dental pulp..Methods: The normal adult pulp tissue, acute and chronic dental pulp tissue specimens of 20 cases were selected clinically. Each sample was divided into two parts. One specimen was observed by light microscope after fixation, embedding, sectioning and HE staining, and the results were the pathological basis of grouping for the normal pulp group, acute pulpitis group and chronic pulpitis group. Another specimen was amplified by RT-PCR. The PCR products were analyzed by 2% agarose gel electrophoresis, observed and took pictures under the ultraviolet lamp, and then compared with the β-actin. The pictures were processed by the gel image analysis system. When β-actin was as standard, calculation of the ratio of CD40 andβ-actin integral density was on behalf of the relative expression of CD40 m RNA in each case in the samples. Statistical software was used for statistical treatment. Results were presented as mean ± standard error(SEM). Pair t test was used to determine the statistical significance of differences. p < 0.05 was considered significant.Results: The results of RT-PCR showed that the relative expression of CD40 m RNA in chronic pulpitis tissues was significantly higher than the normal pulp group and acute pulpitis group, and the differences were statistically significant(P < 0.05). But there was no significant difference between the normal pulp group and acute pulpitis group(P > 0.05).Conclusion: CD40 is involved in the inflammatory response of the pulpitis, and is closely related to the chronic inflammation.