Localization of thrombomodulin in pericryptal fibroblasts of the rat duodenum

Mechanical components of rat intestinal villi as revealed by ultrastructural analysis with special reference to the axial smooth muscle cells in the villi

The ultrastructure of the rat intestinal interstitium with regard to the mechanical components was analyzed from a functional viewpoint utilizing serial horizontal as well as longitudinal sections through the lamina propria mucosae, including both villi and crypts. The axial smooth muscle cells in the villi (villus-axial SMs) exhibited different configurations at various levels of the wall. They were separated from the voluminous fluid-filled spaces by sheet-like processes of fibroblasts in the upper part of the intravillous interstitium, formed a sheet around the central lymphatics, and were covered by the sheet-like processes of fibroblasts in the lower part of the intravillous interstitium. These villus-axial SMs were poorly developed and associated with the lymphatic walls in the upper part of the pericryptal interstitium; they were tapered and connected to microtendons composed of fascicles of longitudinal collagen fibrils in the lower part of pericryptal interstitium. At the apical termination, the villus-axial SMs were connected to myofibloblasts, which sent off many processes into the subepithelial meshwork layer of fine cell processes and extracellular matrices. The villus-axial SMs possibly develop longitudinal tension against the intravillous hydraulic pressure developing from the transepithelial absorption through the intestinal epithelium.

News and views in Histochemistry and Cell Biology

Advances in histochemical methodology and ingenious applications of novel and improved methods continue to confirm the standing of morphological means and approaches in research efforts, and contribute significantly to increasing our knowledge about structures and functions in all areas of the life sciences from cell biology to pathology. Reports published during recent months documenting this progress are summarized in the present review.