| 0810 Iron Metabolism in G551D Cystic Fibrosis Mouse Incisor Ameloblasts | ||
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J. SMID1, W.G. YOUNG1, B.J. MCMORRAN2, and B.J. WAINWRIGHT2, 1School of Dentistry, University of Queensland, Brisbane, Qld, Australia, 2Institute for Molecular Bioscience, University of Queensland, Brisbane, Qld, Australia Homozygous cystic fibrosis (CF) mice are easily discriminated from their litter mates by the abnormal chalky-white appearance of their teeth. The reason for the absence of the enamel iron pigmentation is unclear. Objectives: To assess iron distribution and metabolism in the developing incisors of G551D CF mice. Methods: Mice were bred from crosses between mice heterozygous for the human G551D mutation in the murine cystic fibrosis transmembrane conductance regulator (cftr) gene. Mouse heads were harvested from adult wild type (+/+) and homozygous CF (cftrG551D /cftrG551D) mice. Mouse heads were either bisected sagittally and processed for iron histochemistry and ferritin immunohistochemistry, or maxillary incisors were dissected-out and processed for iron analysis by energy-dispersive x-ray spectrometry (EDS) and inductively-coupled plasma emission-mass spectroscopy (ICP-MS). Results: Iron histochemistry and ferritin immunohistochemistry showed iron distribution in the enamel organ cells of the homozygous CF mice was markedly different to those of the wild type mice. In wild type mice, iron was evident in the enamel organ cells developmentally throughout maturation and reduced enamel organ stages as well as in extracellular enamel remnants. In contrast, in homozygous CF mice tissues, iron staining occurred mainly in maturation ameloblasts. Staining was virtually absent both in the reduced enamel organ cells and extracellularly. However, prior to this latter stage of development, iron staining was present in pools of macrophage-like cells supra-adjacent to underlying bone tissue. ICP-MS analysis indicated that total iron content of homozygous CF mice incisors was approximately 30% of that present in wild type teeth. EDS analysis of the homozygous CF mice incisors failed to detect the superficial iron-rich zone normally present in enamel posterior to the incisal edge. Conclusions: The G551D cystic fibrosis mutation affects iron transport in the ameloblasts of the rodent incisor. This study was supported by the Australian Dental Research Foundation, Inc. | ||
| Seq #70 - Mechanisms of Odontogenesis 11:00 AM-12:00 PM, Thursday, 29 June 2006 Brisbane Convention & Exhibition Centre Exhibit Hall 1 | ||
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