Quantitative analysis and localization of mRNA transcripts of type I collagen, osteocalcin, MMP 2, MMP 8, and MMP 13 during bone healing in a rat calvarial experimental defect model.
The study examined the expression of matrix metalloproteinases (MMPs), type I collagen and osteocalcin during bone healing in a rat calvarial experimental defect model. Twelve-week-old male Wistar rats were used. A full-thickness standardized trephine defect was made in the parietal bone, with the rat under anesthesia. RNA was extracted from tissue that filled the original bone defect on days 1 and 3 and in weeks 1, 2, 3, 5, 8, 10, 12, 18, and 24 and processed for quantitative analysis of expression of type I collagen, osteocalcin and matrix metalloproteinases (MMPs) 2, 8, and 13 by using real-time polymerase chain reaction. Alternatively, the rats were fixed by perfusion through the aorta and resected calvaria were processed for in situ hybridization for these molecules. The expression of type I collagen, osteocalcin and MMPs 2 and 13 increased toward week 2 and decreased thereafter, whereas the expression of MMP 8 was the highest on day 1. The mRNA transcripts of type I collagen and osteocalcin were localized in osteoblasts and osteocytes, some of which expressed MMPs 2, 8, and 13. Osteoblasts and osteocytes may play a role in the remodeling of extracellular matrices with MMPs during healing of a defect in bone.
Itagaki
Tomoko
T
Division of Oral Surgery, Tohoku University Graduate School of Dentistry, Sendai, Japan.
Honma
Takahiro
T
Takahashi
Ichiro
I
Echigo
Seishi
S
Sasano
Yasuyuki
Y
D000818:Animals; D001842:Bone and Bones / Q000201:enzymology / Q000293:injuries / Q000503:physiopathology; D024042:Collagen Type I / Q000235:genetics*; D006259:Craniocerebral Trauma / Q000201:enzymology / Q000503:physiopathology; D053509:Matrix Metalloproteinase 13 / Q000235:genetics*; D020778:Matrix Metalloproteinase 2 / Q000235:genetics*; D020784:Matrix Metalloproteinase 8 / Q000235:genetics*; D010006:Osteoblasts / Q000201:enzymology / Q000502:physiology; D010010:Osteoclasts / Q000201:enzymology / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D012886:Skull / Q000201:enzymology / Q000503:physiopathology; D014158:Transcription, Genetic; D014945:Wound Healing / Q000502:physiology*
D024042:Collagen Type I; D012333:RNA, Messenger; D053509:Matrix Metalloproteinase 13; D020778:Matrix Metalloproteinase 2; D020784:Matrix Metalloproteinase 8