title: Suture cartilage formation pattern varies with different expansive forces.
abstract: BACKGROUND
  Midpalatal suture expansion could induce osteogenesis to correct maxillary insufficiency; cartilage formation could also be induced, and lower-magnitude forces might generate a preferable response pattern. In this study, we aimed for an enhanced understanding of the cartilage formatting effects of expansion.
  
  
  METHODS
  Thirty 6-week-old male C57BL/6 mice were randomly and evenly assigned to 3 groups; the animals in each group received a sustained suture expansion at 0, 10, and 20 g, respectively. Ten additional mice were fed the same as the baseline controls and received no expansion. After 7 days, the animals were killed; coronal paraffin sections were stained using toluidine blue and safranin-O. The proliferating cell nucleus antigen, the nuclear antigen Ki-67, alkaline phosphatase, and matrix metalloproteinase 13 expressions were visualized with immunohistochemistry. All data were analyzed statistically, and the differences were considered significant at P <0.05.
  
  
  RESULTS
  Compared with the control, the cartilage matrix volume was significantly increased by the 20-g expansion, showing increased cartilage matrix and hypertrophic chondrocytes with the highest matrix metalloproteinase 13 expression. The 10-g expansion formed condensed proliferating chondrocyte masses, within which the highest percentages of proliferating cell nucleus antigen and Ki-67 positive cells were present. The 10-g and the 20-g expansions equally intensified the alkaline phosphatase expression.
  
  
  CONCLUSIONS
  The lower expansion (10 g) promoted chondrocyte proliferation and induced a more preferable suture cartilage response pattern compared with the higher expansion (20 g), which just increased the cartilage matrix production.
authors.affiliation: Assistant professor, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Research associate, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Research associate, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Xiao
authors.affiliation: Assistant professor, Department of Orthodontics and Oral Facial Genetics, School of Dentistry, Indiana University, Indianapolis, Ind.
authors.forename: Sean Shih-Yao
authors.initials: SS
authors.lastname: Liu
authors.affiliation: Professor and vice dean, State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China. Electronic address: yhyang6812@scu.edu.cn.
authors.forename: Haiyang
authors.initials: H
authors.lastname: Yu
mesh_terms: D000469:Alkaline Phosphatase / Q000032:analysis; D000818:Animals; D001696:Biomechanical Phenomena; D002356:Cartilage / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D019902:Chondrocytes / Q000502:physiology; D020219:Chondrogenesis / Q000502:physiology*; D004396:Coloring Agents; D003393:Cranial Sutures / Q000502:physiology*; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D053509:Matrix Metalloproteinase 13 / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D010012:Osteogenesis / Q000502:physiology; D010155:Palatal Expansion Technique; D010159:Palate / Q000502:physiology*; D010619:Phenazines; D018809:Proliferating Cell Nuclear Antigen / Q000032:analysis; D011897:Random Allocation; D013314:Stress, Mechanical; D014048:Tolonium Chloride
chemical_list: D004396:Coloring Agents; D019394:Ki-67 Antigen; D010619:Phenazines; D018809:Proliferating Cell Nuclear Antigen; D014048:Tolonium Chloride; D000469:Alkaline Phosphatase; D053509:Matrix Metalloproteinase 13; C507081:Mmp13 protein, mouse; C009195:safranine T