Tissue sampling as a potential source of error in experimental studies of cartilage.

Although it might seem trite to point out that tissue sampling is a potential source of experimental error, this survey disclosed that even experienced investigators in fact often work with cartilage that is contaminated by non-cartilaginous tissue of which they were unaware. Twenty-two specimens ranging from chick embryo sternum to bovine nasal septum were studied by serial sectioning. Eighteen of the 22 contained extraneous tissue comprising from 3 to 50% of the cross-sectional area. The impact of the contamination depends on the use being made of the material and probably is greatest in cell culture studies because chondrocytes and fibroblasts have large differences in population doubling time. Several approaches for minimizing the error are suggested by the findings. Histological examination of specimen material is thus a desirable quality control procedure in the design and interpretation of experiments on cartilage as well as other tissues.