Quantitative histology of the rat thyroid. Influence of histologic techniques on the morphometric data.

The influence of various histologic techniques on the results obtained by morphometric analysis of the rat thyroid gland was studied. The limits of thyroid follicles were more clearly defined in both silver-impregnated paraffin-embedded sections and resin-embedded semithin sections than in routinely stained paraffin-embedded sections, thus enabling more accurate measurements of thyroid structures. Due to its simplicity, the silver impregnation method is clearly useful for histomorphometric studies when large numbers of measurements are involved. C cells were easily identified in paraffin-embedded sections by immunohistochemical staining. The measurement of interstitial tissue in sections without immunostaining of C cells led to an overestimation of the volume fraction of interstitial tissue.