Morphological study of mast cell localization in the wall of the proximal tubule in the domestic swine kidney.

Abstract

Morphological studies to localize mast cells in the wall of the convoluted and straight parts of the proximal tubules of the domestic swine kidney were performed. Kidney perfusion was carried out in 8-month-old pigs and semi-thin and ultrathin sections were prepared after a routine treatment. A light microscopic study showed that mast cells were not frequently found. Most were localized in the wall of the proximal convoluted tubule, while in the proximal straight tubule wall they were fewer in number. Most of the mast cells were oval in shape, their size being typical for this species, and the granules were reddish in colour. Three types of granule containing an evenly distributed granular-fibrous substance were found by TEM examination: the first type had a single electron-optically dense belt under the membrane; the second showed optically empty spaces between the substance and the cell membrane; the granules from the third type had two parallel dense belts below the granular membrane and were the smallest in size. Some of the granules of the first type were connected with the granular endoplasmic reticulum. A very narrow intercellular area and single desmosome-like junctions were found between the mast cells and the epithelial cells. Protrusions of plasmalemma and granules outside the cells were not established. On the basis of these results and data from the scientific literature, a comparative analysis was carried out. This showed certain differences between the results obtained and previous findings on the morphology of domestic swine mast cells and granules.