Effect of photodynamic therapy on the morphological changes of periapical inflammation: An experimental study in rats
PHOTODIAGNOSIS AND PHOTODYNAMIC THERAPY
Authors: Khan, Sultan Zeb; Karim, Samina; Mirza, Sana
Abstract
Aim: We aimed to explore the morphological changes with photodynamic therapy (PDT) in experimentally produced periapical lesions in rats, and to investigate if PDT used as an adjunct to conventional root canal debridement helps to enhance healing the inflammatory response around root apex of rats. Materials and Methods: Sixty adult Sprague-Dawley male rats (70-90 days/140-160 g) were experimented. Pulp was removed from the mesial root of the first maxillary molar and left open to oral environment to allow the formation of periapical lesion. The rats were numbered and randomly divided into two groups: (i) PDT group (n = 30) received a single session of PDT with conventional debridement and, (ii) Control group (n = 30) received conventional debridement but with no PDT. PDT application involved the use of methylene blue photosensitizer for 5 min inside the root canals and irradiated with diode laser of 805 nm and 20 W power output for 90 s and sealed. After 4 weeks, the experimental rats were sacrificed by cervical dislocation. The maxillary first molar was then collected along with the surrounding tissue for further processing. Hematoxylin and eosin and immunohistochemical staining were used to observe the morphological effects. Proliferating Cell Nuclear Antigen (PCNA), STRO-1 and CD-44 were used as the primary antibodies for the immunohistochemical study. Results: A reduction in inflammatory cells, which were mainly composed of lymphocytes, was observed in the periapical lesions after PDT. The number of PCNA-positive cells increased to approximately twice in the PDT as compared to the control group. These PCNA-positive cells included STRO-1 and CD-44 positive cells, indicating enhancement of wound healing and reduction in inflammatory cells. Conclusion: The findings of the present experimental study indicate that PDT application induced proliferation of PCNA-positive cells, which included STRO-1 and CD44-positive cells. This suggests that PDT may help to enhance healing periapical lesion, indicating the potential of PDT in the treatment of periapical periodontitis.
TGF-beta induced EMT and stemness characteristics are associated with epigenetic regulation in lung cancer
SCIENTIFIC REPORTS
Authors: Kim, Bit Na; Dong Hyuck Ahn; Kang, Nahyeon; Yeo, Chang Dong; Kim, Young Kyoon; Lee, Kyo Young; Kim, Tae-Jung; Lee, Sug Hyung; Park, Mi Sun; Yim, Hyeon Woo; Park, Jong Y.; Park, Chan Kwon; Kim, Seung Joon
Abstract
Transforming growth factor-beta (TGF-beta) promotes tumor invasion and metastasis by inducing epithelial-mesenchymal transition (EMT). EMT is often related with acquisition of stemness characteristics. The objective of this study was to determine whether EMT and stemness characteristics induced by TGF-beta might be associated with epigenetic regulation in lung cancer. A human normal lung epithelial cell line and four lung cancer cell lines were treated with TGF-beta. Transcriptome analysis of BEAS-2B and A549 cells incubated with TGF-beta were analyzed through next-generation sequencing (NGS). Western blotting was carried out to investigate expression levels of epithelial and mesenchymal markers. Wound healing and Matrigel invasion assay, sphere formation assay, and in vivo mice tumor model were performed to evaluate functional characteristics of EMT and stemness acquisition. To investigate whether activation of EMT and stem cell markers might be involved in epigenetic regulation of lung cancer, experiment using a DNA methyltransferase inhibitor (5-azacytidine, AZA), methylation-specific PCR (MSP) and bisulfite sequencing were performed. NGS revealed changes in expression levels of EMT markers (E-cadherin, N-cadherin, fibronectin, vimentin, slug and snail) and stem cell markers (CD44 and CD87) in both BEAS-2B and A549 cells. Functional analysis revealed increased migration, invasion, sphere formation, and tumor development in mice after TGF-beta treatment. Expression of slug and CD87 genes was activated following treatment with AZA and TGF-beta. MSP and bisulfite sequencing indicated DNA demethylation of slug and CD87 genes. These results suggest that TGF-beta induced EMT and cancer stemness acquisition could be associated with activation of slug and CD87 gene by their promoter demethylation.