The Effects of Irradiation and Calcium-deficient Diet on the Expression of Bone Morphogenetic Protein-2/4 during Early Tooth Development

Park, Dai Hee; Hwang, Eui Hwan; Lee, Sang Rae

Abstract

PURPOSE: To investigate the expression of bone morphogenetic protein(BMP)-2/4 during eary tooth development after irradiation and calcium-deficient diet.
MATERIALS AND METHODS
The pregnant three-week-old Sprague-Dawley rats were used for the study. The control group was non-irradiation/normal diet group(Group 1), and the experimental groups were irradiation/normal diet group(Group 2) and irradiation/calcium-diet group(Group 3). The abdomen of the rats at the 9th day of pregnancy were irradiated with single dose of 350 cGy. The rat pups were sacrificed at embryonic 18 days, 3 days and 14 days after delivery and the maxillae tooth germs were taken. The tissue sections of specimen were stained immunohistochemically with anti-BMP-2/4 antibody.
RESULTS
At embryo-18 days, immunoreacivity for BMP-2/4 of the Group 1 was modetate in stratum intermedium of dental organ and weak in dental papilla and dental follicle, but that of Group 2 was weak in cell layer of dental organ, and no immunoreacivity was shown in dental papilla and dental follice of Group 2 and in all tissue components of the Group 3. At postnatal-3 days, immunoreacivity for BMP-2/4 of the Group 1 was strong in cell layer of dental organ, odontoblasts and developing alveolar bone, but that of Group of 2 and Group 3 was weak in odontoblasts and developing alveolar bone. At postnatal-14 days, immunoreacivity for BMP-2/4 of the Group 1 was strong in newly formed cementum, alveolar bone and odontoblasts, but that of Group 2 was weaker than that of Group 1. In the Group 3, tooth forming cell layer showed weak immunoreactivity, but other cell layers showed no immunoreactivity.
CONCLUSION
The expression of bone morphogenetic protein(BMP)-2/4 during early tooth development was disturbed after irradiation and calcium-deficient diet.