Korean J Orthod.  1996 Apr;26(2):187-196.

The immunohistochemical expression of collagens and the morphogenesis in the developing mandible of human embryos and fetuses

• Kook YA
• Kim SC
• Kim EC
• Kim OH
• Kim JG

Abstract

Underlying malocclusions and dentofacial deformities are often related to variations in the craniofacial development. Type I and type II collagens are considered the major collagens of bone and cartilage respectively. Monitoring the patterns of those protein expressions during development will provide a basis for the understanding of normal and abnormal growths. This study was undertaken to investigate the morphogenetic changes and the expression patterns of type I and II collagen proteins involved in the developing mandible of human embryos and fetuses. 50 embryos and fetuses were studied with Hematoxylin and Eosin, Alcian blue-PAS, Masson Trichrome, and lmmunohistochemical stains. The results were as follows: 1. A 13.5 mm embryo showed the stomatodeum with dental lamina, maxillary and mandibular processes. Meckel's cartilage appeared in the mandibular arch of a 20.5 mm embryo. New bone formation was bilaterally initiated at the outer side of middle portion of Meckel's cartilage of 22-38mm embryos. 2. Meckel' cartilage was resorbed at the 15th week fetus. The endochondral ossification was observed where there was direct replacement of cartilage by bone. Meckel' cartilage disappeared and membraneous ossification were observed at the 25th week. 3. Before the appearance of Meckel's cartilage, the expression of type I collagen was moderate at the odontogenic epithelium of maxillary & mandibular process, but mild for the expression of type II collagen. 4. During the appearance of Meckel's cartilage and new bone formation, the immunoactivity of type II collagen was more expressed than type I collagen at the Meckel's cartilage and new bone. 5. During intramembranous bone formation, the expression of type II collagen was rare in the bony trabeculae. There was a switch for the expression of collagens from type II to type I during the appearance of Meckel's cartilage.

Keyword

Human Embryo and Fetus; Developing Mandible; Meckel' Cartilage; Morphogenesis; Type I and II collagen

MeSH Terms

Cartilage
Collagen Type I
Collagen Type II
Collagen*
Coloring Agents
Dentofacial Deformities
Embryonic Structures*
Eosine Yellowish-(YS)
Epithelium
Fetus*
Hematoxylin
Humans*
Malocclusion
Mandible*
Morphogenesis*
Osteogenesis
Collagen
Collagen Type I
Collagen Type II
Coloring Agents
Eosine Yellowish-(YS)
Hematoxylin