Thesis or Dissertation Initial Transient Accumulation of M2 Macrophage-associated Molecule-expressing Cells after Pulpotomy with Mineral Trioxide Aggregate in Rat Molars

Takei, Erika  ,  武井, 絵梨花

pp.1 - 25 , 2015-03-23 , 新潟大学
学位の種類: 博士(歯学). 報告番号: 甲第4003号. 学位記番号: 新大院博(歯)甲第316号. 学位授与年月日: 平成27年3月23日
Journal of endodontics. 2014, 40(12), 1983-1988.
Introduction: M2 (alternatively-activated) macrophages are known to participate in wound healing and tissue repair. This study aimed to analyze the temporospatial changes in the distribution and density of M2 macrophage-associated molecule-expressing cells after pulpotomy with mineral trioxide aggregate (MTA) in rat molars, in order to ascertain the role played by M2 macrophages in the healing of MTA-capped pulp tissue. Methods: The maxillary first molars of 8-week-old Wistar rats were pulpotomized and capped with MTA. After 1-14 days, the teeth were examined after hematoxylin-eosin staining or immunoperoxidase staining of CD68 (a general macrophage marker) and M2 macrophage markers (CD163 and CD204). The density of positively-stained cells was enumerated in the surface and inner regions (0 -100 µm and 300-400 µm, respectively, from the wound surface). Results: MTA-capping initially caused mild inflammatory changes and the formation of a degenerative layer, followed by progressive new matrix formation and calcified bridging. At 1-2 days, CD68-, CD163-, and CD204-positive cells started to accumulate beneath the degenerative layer, and the density of these cells was significantly higher in the surface region than in the inner region (P < 0.05). From 7 days onwards, the three types of cells displayed an almost normal distribution beneath the newly dentin-like matrix. Conclusions: After the pulpotomy of rat molars with MTA, M2 macrophage-associated molecule-expressing cells transiently accumulated beneath the degenerative layer under the MTA. This suggests that M2 macrophages participate in the initial phases of the healing of MTA-capped pulp tissue.

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