New inclusion body in a rat renal cell

In an effort to review ultrastructural features of cells in the kidney of a male rat, transmission electron microscopy was used to study ultrathin sections.

One light cell in a collecting tubule contained a 2.3-microns long linear array of electron-dense asymmetric structures in a granular zone of greater electron density than the general cytoplasm. This inclusion body could be interpreted to consist of a parallel array of 100-150-nm x 24-nm electron-dense rodlets, or a parallel array of 100-150-nm x 67-nm tubules. The inclusion showed no association with any cell organelle. The origin, chemical nature, frequency of occurrence, and functional significance of this inclusion are unknown.

Although this inclusion body somewhat resembles previously described inclusions or granules, the differences in dimensions, frequency, and relation to other cell structures suggest it is a new observation.