Quantitative histochemical study of changes with age in intracellular lipids of xiphisternal cartilage in rat and rabbit.

Histological and histochemical methods have been employed to study the histology and intracellular lipid distribution of xiphisternal cartilage in rats and rabbits of 5 different ages ranging from newborns to old adults. Xiphisternal cartilage was subdivided for the purposes of the study in 12 regions, and observations were quantified using an image analyser. Large differences in intracellular lipid distribution were observed among different cell populations of individual regions, among different regions of individual cartilages, and among cartilages from animals of different ages. The 2 species studied also differed widely as regards the distribution and quantity of intracellular lipids, even with respect to regions of similar histological characteristics occupying the same relative position within the cartilage. In particular, in the rat the chondrocytes of the lateral edges an the distal third are those possessing the greatest amounts of triglycerides whereas in rabbit these regions are the least rich in triglycerides.