title: [Polarized microscopic observation of the collagen change in bone healing during bone lengthening].
abstract: OBJECTIVE
  To investigate the feature and regularity of the collagen change in bone healing during bone lengthening.
  
  
  METHODS
  Bone lengthening model was made in the middle segment of the rabbit tibia. Five days after the model was established, the bone was lengthened 1.5 mm per day for 14 days. The rabbits were put to death after elongation, 7, 14, 21, 30, 40, 50, 60 and 70 days after elongation. The distracted area of the bone was imbedded with paraffin. After being stained by the picric acid-sirius red staining, the slice was observed under polarized microscope.
  
  
  RESULTS
  The features of the collagen change in the distracted bone were as follows: (1) In the fibrous tissue of the distracted area during lengthening period and the early stage after lengthening, there was not only collagen III but also much collagen I. (2) Collagen I , II and III were observed in the cartilage. (3) Collagen I, II and III were also observed in the pseudo-growth plate. (4) Collagen I took the dominance during lengthening period and the late stage after lengthening.
  
  
  CONCLUSIONS
  New bone formation in bone lengthening is under the distracted force, so the collagen changes have different features compared with that in fracture healing. Collagen I, II and III can be identified by picric acid-sirius red staining and polarized microscope, so a new method for studying the collagen typing in bone repairing is provided.
authors.affiliation: Orthopedic Center of PLA, Kunming General Hospital of Chengdu Military Region, Kunming Yunnan 650032, PR China. zoupei001@163.com
authors.forename: Pei
authors.initials: P
authors.lastname: Zou
authors.forename: Junhui
authors.initials: J
authors.lastname: Li
authors.forename: Zhuyi
authors.initials: Z
authors.lastname: Li
mesh_terms: D000818:Animals; D001852:Bone Lengthening; D001862:Bone Resorption; D003094:Collagen / Q000378:metabolism*; D024042:Collagen Type I / Q000378:metabolism; D024043:Collagen Type II / Q000378:metabolism; D024061:Collagen Type III / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D017102:Fracture Healing; D008297:Male; D008859:Microscopy, Polarization; D011817:Rabbits; D013977:Tibia / Q000293:injuries / Q000378:metabolism / Q000473:pathology*
chemical_list: D024042:Collagen Type I; D024043:Collagen Type II; D024061:Collagen Type III; D003094:Collagen