IADR Abstract Archives
Quantifying Enamel Pigment Differences in Amelogenin Null and Transgenic Mice
Objectives: 1) Quantify enamel pigment of WT, Amelx null (KO) and transgenic (Tg)/KO mice, and 2) determine whether lack of pigment in mutant incisor enamel is associated with decreased enamel iron content.
Methods: Adult mouse incisors extracted from WT (n=20), KO (n= 17) and Tg (M180, CTRNC or LRAP)/KO (n≥3) mice, were air-dried and mounted in black molding clay. 2D images were taken with a Canon EOS7D camera with 65-mm macro lens and calibrated against a standardized white tile. Images opened in Adobe Photoshop were divided into three equal segments. Calibrated CIELAB L (lightness), A (green/red), and B (blue/yellow), and WI (whiteness) values were calculated. ANOVA was used to test for statistical significance. FTH1 antibody was used to detect iron in enamel from decalcified paraffin-embedded WT, KO and Tg/KO mandibles from 5 day-old and adult mice.
Results: Significant differences were consistently observed between pigments of WT and both KO and Tg/KO incisors, particularly the B and WI parameters in the incisal segments (p<0.05). FTH1 staining was observed in odontoblasts and late secretory and maturation stage ameloblasts in incisors and molars. FTH1 staining was strongest in WT incisor ameloblasts compared to mutants and dependent on genotype.
Conclusions: We have quantified enamel pigment differences between WT, KO and Tg/KO mice, which appear related to differing iron content in outer enamel. Further investigation is required to determine the mechanism by which iron gets incorporated into WT enamel and causes of alterations in AI mouse models.
Methods: Adult mouse incisors extracted from WT (n=20), KO (n= 17) and Tg (M180, CTRNC or LRAP)/KO (n≥3) mice, were air-dried and mounted in black molding clay. 2D images were taken with a Canon EOS7D camera with 65-mm macro lens and calibrated against a standardized white tile. Images opened in Adobe Photoshop were divided into three equal segments. Calibrated CIELAB L (lightness), A (green/red), and B (blue/yellow), and WI (whiteness) values were calculated. ANOVA was used to test for statistical significance. FTH1 antibody was used to detect iron in enamel from decalcified paraffin-embedded WT, KO and Tg/KO mandibles from 5 day-old and adult mice.
Results: Significant differences were consistently observed between pigments of WT and both KO and Tg/KO incisors, particularly the B and WI parameters in the incisal segments (p<0.05). FTH1 staining was observed in odontoblasts and late secretory and maturation stage ameloblasts in incisors and molars. FTH1 staining was strongest in WT incisor ameloblasts compared to mutants and dependent on genotype.
Conclusions: We have quantified enamel pigment differences between WT, KO and Tg/KO mice, which appear related to differing iron content in outer enamel. Further investigation is required to determine the mechanism by which iron gets incorporated into WT enamel and causes of alterations in AI mouse models.