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Differentiative potentials of neural crest derived mandibular ectomesenchymal cells of the chick (Gallus domesticus), with special reference to cartilage and bone.

Date

1990

Authors

Ekanayake, Sunetra.

Journal Title

Journal ISSN

Volume Title

Publisher

Dalhousie University

Abstract

Description

Mandibular ectomesenchymal cells of the chick were studied in vitro to achieve two goals; (1) to understand the capability of these cells to differentiate into cartilage and bone in vitro and (2) to determine the nature of commitment of these cells to differentiate into cartilage, bone and other tissue types. Micromass cultures of cells at three developmental stages; HH 17, 22 and 26 were used to understand the differentiation of various tissues in mandibular mesenchyme. In this part of the study, quail mandibular mesenchymal cells were also used to compare with those of chick. The nature of the commitment of mandibular ectomesenchymal cells was studied by clonal culture. Histological, histochemical and immunohistochemical methods were used to determine the presence of various cell and tissue types in micromass cultures and in clones.
It is evident from the present study that mandibular mesenchymal cells of chick and quail can be maintained in vitro. When cultured at high cell densities, they differentiate into various tissue types which include cartilage, bone, connective tissue and skeletal muscle cells, depending on the stage of development of the mesenchymal cells used. However, the majority of cells in all the micromasses were fibroblasts which contained high levels of alkaline phosphatase enzyme activity.
When isolated single mesenchymal cells from chick HH 17 were cultured on 3T3 feeder layers, cells began to proliferate efficiently and produced clones. Most of the clones readily underwent chondrogenesis. Cloned cells maintained proliferation even after differentiating into chondrocytes. There were three main types of clones produced by chick HH 17 mandibular mesenchymal cells: (1) clones containing only chondrocytes, (2) clones containing only fibroblasts and (3) clones containing a mixture of chondrocytes and fibroblasts. Therefore, the mandibular mesenchymal cell population at HH stage 17 is heterogeneous, containing a mixture of bipotential and unipotential cells. In clonal culture, bipotential cells gave rise to clones with chondrocytes and fibroblasts. However, whether bipotential chondrogenic mother cells are capable of giving rise to bone is not clear. Mesenchymal cells obtained from non-hypertrophic regions of the mandible underwent hypertrophy under clonal cell culture conditions.
Thesis (Ph.D.)--Dalhousie University (Canada), 1990.

Keywords

Biology, Cell.

Citation