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Cell kinetics of growth cartilage of achondroplastic (cn) mice
Journal of Anatomy
|May 1, 1985
Abstract:
Mice homozygous for the recessive gene achondroplasia (cn) aged 16 and 17 days and some homozygotes aged 22-34 days have disruptions in the growth of the proximal tibial growth plate which are due solely to reduced hypertrophic cell height. A second class of homozygote, distinguishable at 22 days, has a greater disruption due to much reduced hypertrophic cell height, reduced labelling index and reduction of the number of cells in the effective proliferative zone.
Insights
Achondroplasia (cn) in mice disrupts tibial growth plate development. Reduced hypertrophic cell height is the primary cause, with some mice also showing reduced proliferation zones.
Area of Science:
- Skeletal biology
- Developmental biology
- Genetics
Background:
- Achondroplasia is a genetic disorder affecting bone growth.
- The (cn) mouse model exhibits achondroplasia, providing insights into skeletal development.
Purpose of the Study:
- To investigate the cellular mechanisms underlying tibial growth plate abnormalities in achondroplasia (cn) mice.
- To differentiate the severity and cellular basis of growth plate disruption in different age groups of (cn) homozygotes.
Main Methods:
- Histological analysis of proximal tibial growth plates from (cn) homozygous mice at 16-17 days and 22-34 days.
- Assessment of hypertrophic cell height, proliferative zone cell numbers, and labeling index.
Main Results:
- Mice aged 16-17 days and some older homozygotes showed reduced hypertrophic cell height, solely impacting growth plate elongation.
- A distinct subgroup of homozygotes at 22 days displayed more severe disruption, characterized by significantly reduced hypertrophic cell height, decreased labeling index, and fewer proliferative cells.
Conclusions:
- The achondroplasia (cn) mutation primarily affects hypertrophic chondrocyte differentiation and proliferation in the tibial growth plate.
- Heterogeneity exists in the cellular manifestations of achondroplasia, with distinct phenotypes observed based on age and severity.