Abstract

The distribution, histochemistry, and functional properties of oral (cheeks, soft palate, and tongue) mast cells (MC) was compared to those of peritoneal, cutaneous, and intestinal MC. The ultrastructure of oral MC was also studied. Fresh tissue and peritoneal cells were fixed either in absolute ethanol or in periodate lysine 2% paraformaldehyde and embedded in paraffin. For electron microscopy, specimens were fixed in 1% glutaraldehyde in formol and embedded in epon. Serial paraffin sections were stained with Giemsa, toluidine blue (0.5% and 0.005%), astra blue/safranin, alcian blue/safranin, berberine sulfate, safranin alone, and fluorescein-labelled avidin to determine the staining properties, incidence, and distribution of both connective tissue-type MC and mucosal-type MC at these sites. Oral, peritoneal, and cutaneous MC granules stained positively with Giemsa, toluidine blue (0.5 and 0.005%), alcian blue, astra blue, berberine sulfate, safranin used alone, and avidin-FITC, but failed to stain with safranin when used in sequence with alcian blue or astra blue. Intestinal MC stained with the same dyes as oral MC except for 0.005% toluidine blue, berberine sulfate, and safranin. Oral and lingual MC are located in the deep lamina propria, around blood vessels and salivary secretory ducts, in close association with nerve endings, and between muscle fibers. In the cheeks and soft palate, but rarely in the tongue, MC were also found around and between glandular acini. MC constitute a predominant immune component in oral tissues, being more numerous in the soft palate and cheek-labial junction (4800/mm3) and in the tongue (4000/mm3), than in the duodenal mucosa (2650/mm3).(ABSTRACT TRUNCATED AT 250 WORDS)