title: Ultrastructural variations of the urothelial membrane in essential fatty acid (EFA)-deficient rats. A digital densitometric study.
abstract: The present report deals with a densitometric study of the ultrastructural images of the urothelial membrane of rats in the following experimental conditions: (1) EFA-deficient (EFAD) rats; (2) EFA-sufficient (EFAS) rats; and (3) EFAD rats that were fed the EFAD diet for 30 weeks and received an EFAS diet for the following 10 weeks (EFAD/S group). On electron micrographs of the transitional epithelium of ureters and urinary bladder of these rats, optical density (OD) profiles of the urothelial unit membrane were recorded and digitized using a computer-controlled microdensitometer with a solid-state self-scanned photodiode array sensor. A Gaussian curve was adopted as a model for the distribution of electron-dense material in each osmiophilic leaflet. Gaussian parameters were used to estimate the thickness of the urothelial membrane and of each osmiophilic leaflet, and the amount of electron-dense material and the maximal electron density present in each leaflet. In EFAS rats, the thick urothelial membrane was asymmetric like that of the normal, resulting from a greater thickness of the outer leaflet and a greater electron density of the cytoplasmic one. In EFAD rats, a loss of the characteristic ultrastructural asymmetry and a decrease of the total thickness of the unit membrane were detected. These changes were partially reversed in the EFAD/S rats.
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000648:ultrastructure*; D003720:Densitometry; D004848:Epithelium / Q000648:ultrastructure; D005228:Fatty Acids, Essential / Q000172:deficiency*; D007091:Image Processing, Computer-Assisted; D008854:Microscopy, Electron; D051381:Rats; D011919:Rats, Inbred Strains; D014513:Ureter / Q000648:ultrastructure*; D001743:Urinary Bladder / Q000648:ultrastructure*
chemical_list: D005228:Fatty Acids, Essential