Quantitative morphological and histochemical study of the xiphisternal cartilage and its intracellular lipids in the guinea-pig.

The xiphisternal cartilages of newborn, suckling, immature and adult guinea-pigs were divided into twelve regions in a study of their histology and intracellular lipid content. Histochemical methods were employed, and the observations quantified using a semi-automatic image analyser. In general, triglyceride content increases with age and is lower in surface layers and in distal and lateral regions than in deep layers and proximal and medial regions. Phospholipids, on the other hand, diminish with age and are most abundant in surface layers and in distal and lateral regions. The nature and quantity of these lipids in the various regions and layers into which the cartilages were subdivided has been related to the size of the lacunae in which the cells lie.