Yasunori Momose

Light microscopic radioautographic study of the localization of an anti-allergic agent, Tranilast, in rat mast cells

SummaryIn order to demonstrate the localization of an anti-allergic agent, Tranilast, in the mast cells, light microscopic radioautography was performed. The mast cells collected from rat peritoneal cavity were incubated for 0 to 60 min in a medium containing3H-Tranilast. After the incubation, they were fixed, embedded and processed for light microscopic radioautography. The radioautographic silver grains were frequently localized around and over the cytoplasmic granules and their number increased according to the prolongation of incubation time. From the results obtained at present it was demonstrated that Tranilast was rapidly taken into the cytoplasm of mast cells. This phenomenon may suggest an important role of this agent in the inhibition of allergic reactions of mast cells.

Modulation of morphology, proliferation and collagen synthesis in fibroblasts by the exudate from hypersensitive granulomatous inflammation in rats

We examined the effects of the exudate, collected from rats in which hypersensitive granulomatous inflammation was induced by methylated bovine serum albumin, on the function of inflammatory fibroblasts in culture. Addition of the exudate to the fibroblast culture induced changes in fibroblast morphology, identified by staining with antirat prolyl hydroxylase. Phase-contrast microscopy revealed that the exudate-treated fibroblasts became elongated and formed a network. Scanning electron microscopy showed that numerous long pseudopods covered the surface of the fibroblasts. Transmission electron microscopy revealed microfilament bundles with dense zones parallel to the long axis of the cell and nuclei with folds and indentations. Microfilaments were also visible in the elongated pseudopods. These features were consistent with those of myofibroblasts. The exudate also stimulated fibroblast proliferation and collagen synthesis. These findings suggest that the exudate contained certain factors that modulated fibroblast morphology, proliferation, and collagen synthesis. It is possible that putative endogenous factor(s) at the sites of inflammation modulate the development, contraction, and fibrosis of granulation tissue in hypersensitive granulomatous inflammation.