Cytoskeleton of podocytes in vertebrate animals and human.

Using TEM and immunofluorescence microscope, a study was made on podocytes in vertebrates where an intermediate-sized filament system is replaced by a microtubule system, accompanied by highly developed microfilaments structures. A comparative immunofluorescence study was carried out on cryotome renal sections of plaice (Pleuronectes platessa L.) and rats, using specific antibodies anti-cytokeratins and anti-vimentin. With polyclonal anti-vimentin serum the capillaries of the renal glomeruli showed a bright colour of plaice and only a week one in the rats. Double staining of renal tissue of mongrel rats of different ages (6-7 weeks and 1.8 years old) with antibodies for actin and anti-vimentin polyclonal serum revealed in young rats an intensive fluorescence for actin and a slight fluorescence for the intermediate filaments. Renal glomeruli of old rats demonstrate a strong vimentin-activity and lower actin one. The ultrastructural study of human podocytes showed two different cytoskeleton age-depending types (2, 4, 6, 37 and 65 years old). It is suggested that during individual development and ageing in kidneys of higher animals and human, physiological changes induce morphological cytoskeleton restructuration accompanied by intensive development of intermediate filaments and simultaneous "involution" of microtubules and microfilaments.