Upregulation of tissue-type plasminogen activator in inflamed human dental pulps

Aim: To compare tissue-type plasminogen activator (t-PA) expression in normal human pulp and inflamed human pulp tissue specimens. Methodology: Thirty pulpal tissue specimens (13 normal and 17 inflamed pulps) were obtained from extracted third molars. The levels of t-PA between normal pulp and inflamed pulp tissues were compared using the quantitative reverse-transcriptase polymerase chain reaction analysis. In addition, immunohistochemistry was used to identify the in situ localization of t-PA expression in pulp specimens. Wilcoxon-Mann-Whitney rank sum test was applied for the statistical analysis of the results. Results: t-PA mRNA gene was found more in inflamed pulps when compared with normal pulp tissue (P < 0.05). The results from immunohistochemistry demonstrated that t-PA expression was significantly higher in the inflamed pulp (P = 0.025). t-PA stain was detected in the fibroblasts, inflammatory infiltrates and endothelial cells. Conclusions: t-PA expression was significantly higher in inflamed pulp tissue. t-PA may play an important role in the pathogenesis of pulpal inflammation.