Cell kinetics of growth cartilage in stumpy: a new chondrodystrophic mutant in the mouse

The proximal growth plates of the tibiae in normal and stumpy mice aged 10-41 days were studied. Autoradiographic studies using tritiated thymidine enabled the size of the proliferating cell population and the labelling indices of the growth plates to be determined. Hypertrophic cell heights were also measured. From these data the overall growth rates for the proximal growth plate of the tibia in normal and stumpy mice were calculated. It was found that the major factor responsible for the reduced growth rate in stumpy up to 21 days was the small hypertrophic cell height, while cell proliferation zone size and labelling indices were of minor importance. Histological observations also revealed a lack of organised endochondral ossification, which worsens with age.