Ultrastructure of rat renal tubular basement membrane--meshwork structure demonstration by negative staining.

The tubular basement membrane (TBM) (i.e. tubular basal lamina) of rat kidney was shown to be a fine meshwork by electron microscopy after negative staining. Strands of the meshwork formed a regular three dimensional lattice work. The pores of the meshwork were polygonal. There were two main pore sizes: one approximately 30 A in diameter, the other 42--60 A. In view of our previous observation that glomerular and alveolar basement membranes were made up fine meshwork, it is quite possible that the basement membranes of other organs are also made up such fine meshwork.