Imaging Science in Dentistry

Korean Academy of Oral and Maxillofacial Radiology (대한영상치의학회)
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Apoptosis in the craniofacial tissues of irradiated growing rats

  • Heo Min-Suk (Department of Oral and Maxillofacial Radiology, Bk21, Dental Research Institute, College of Dentistry, Seoul National University) ;
  • Choi Hang-Moon (Department of Oral and Maxillofacial Radiology, Bk21, Dental Research Institute, College of Dentistry, Seoul National University) ;
  • Lee Sam-Sun (Department of Oral and Maxillofacial Radiology, Bk21, Dental Research Institute, College of Dentistry, Seoul National University) ;
  • Choi Soon-Chul (Department of Oral and Maxillofacial Radiology, Bk21, Dental Research Institute, College of Dentistry, Seoul National University) ;
  • Park Tae-Won (Department of Oral and Maxillofacial Radiology, Bk21, Dental Research Institute, College of Dentistry, Seoul National University)
  • Published : 2001.12.01
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Abstract

Purpose: The purpose of this study was to investigate the apoptosis induction in tissues constituting the craniofacial region of growing rat by irradiation. Materials and Methods: The submandibular gland, brain, articular cartilage of condylar head, and calvarium were extracted from 20-day-old rats irradiated 10 Gy. Apoptosis of each tissue was examined by DNA fragmentation and estimated quantitatively using apoptotic index on TUNEL assay. Apoptotic index of each tissue was calculated by the equation for apoptotic cells/total cells × 1,000 on the images of confocal laser scanning microscopy. Apoptotic index was analyzed statistically according to the time lapse after irradiation on the tissues. Results : In the submandibular gland, apoptotic index was significantly increased from 6 hours after irradiation showing the highest value at 12 hours and decreased to the control level at 3 days after irradiation. In the brain, apoptotic index was abruptly reached to the maximum value at 6 hours after irradiation and decreased to the control level at 4 days after irradiation. Articular cartilage and calvarium showed no or little apoptotic signals. The results obtained by the apoptotic index accorded with that of DNA fragmentation. Conclusion : Radiation was closely related with the apoptosis of submandibular gland and brain but, not related with the apoptosis of the articular cartilage of condylar head and calvarium. The changes induced by radiation of the hard tissues would not be explained by apoptosis.

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