Fig 1.
Total collagen I content is reduced in double-null PDL.
Representative Picro Sirius Red (PSR) stained images of 1-month PDL from wt/wt (A), wt/ko (B), ko/wt (C), and ko/ko (D) viewed under polarized light. Images taken at 40X magnification. n = 5 mice/genotype, 5 sections/mouse. Bar in A = 25 μm and applies to all panels. E. Total collagen I content of PDL at 1-, 3-, and 12-month age points. *p<0.05 compared to wt/wt. #p<0.05 compared to ko/ko.
Fig 2.
A consistent reduction in collagen I fiber size observed in double-null PDL from 1-month to 12-months of age.
Collagen fiber morphology represented by thin vs. thick fibers quantified from PSR histology for three age points. n = 5 mice/genotype, 5 sections/mouse. *p<0.05 compared to wt/wt counterparts, #p<0.05 compared to single transgenics.
Fig 3.
Collagen fiber morphology altered in double-null PDL at 1- and 12-month age points.
Representative images of Herovici stained PDL from wt/wt (A&E), wt/ko (B&F), ko/wt (C&G), and ko/ko (D&H) shown at 1- and 12-months of age respectively. Red/pink stain indicates thicker collagen fibers; blue stain indicates thinner collagen fibers, nuclei stain black. Images captured at 40X and oriented with alveolar bone on bottom, PDL center, and tooth cementum on top. Bar in A&E = 25 μm and applies to all panels. n = 3 mice/genotype, 5 section/mouse.
Fig 4.
Mechanical force of tooth extraction varies among transgenic PDL.
Quantification of n = 4 mice, 2 replicates/mouse. *p<0.05 compared to wt/wt, #p<0.05 compared to single transgenics.
Fig 5.
Ki67 expression is increased in single- and double-transgenic murine PDL.
Representative images of Ki67 immunohistochemistry localized in sections of PDL from wt/wt (A), wt/ko (B), ko/wt (C), and ko/ko (D) 1-month mice. All images are oriented with tooth on top, PDL center, and alveolar bone on bottom; 40X magnification. Bar in A = 100 μm and applies to all panels. E. Quantification of n = 5 mice/genotype, 5 sections/mouse. *p<0.05 compared to wt/wt, #p<0.05 compared to single transgenics.
Fig 6.
Number and size of epithelial rests of Malassez (ERMs) varies in murine periodontal ligament (PDL).
Representative sections from 1 month wt/wt (A), wt/ko (B), ko/wt (C), and ko/ko (D) PDL stained with H&E. Black arrows indicate multi-cellular ERMs. Bar in A = 25 μm and applies to all panels. Representative images from 1 month PDL stained for cytokeratin immunoreactivity (green); wt/wt (E), wt/ko (F), ko/wt (G), ko/ko (H). Nuclei stained blue (DAPI). White arrows indicate multi-cellular rests of Malassez expressing cytokeratin. Images are representative of n = 3 mice/genotype. I. Quantification of average number of rests present in sampled PDL. J. Percent of PDL area occupied by rests. n = 5. *p<0.05 compared to wt/wt, #p<0.05 compared to single transgenics.