Model h 7100

At the 14th week, 5 rats from each group were randomly selected and their tails were sampled. The tails of rats were dissected for histopathologic examination to ascertain demyelination or axonal degeneration. The dissected nerves were cleaned with 4% paraformaldehyde-glutaraldehyde (4℃, phosphate buffer, pH 7.4) and post-fixed with 1% OsO₄ (4℃, phosphate buffer). After fixation, the specimens were washed a few times in the same buffer, and then, they were dehydrated with numerous ascending alcohol passages. Propylene oxide was added and the tail samples were embedded in Epon. Embedded sections were cut using an ultramicrotome and stained with 1% Toluidine blue, and nerve specimens were observed with a light microscope. Ultramicrotomy sections were produced, double stained using uranyl acetate and lead citrate, and were observed with a transmission electron microscope, Model H-7100 (Hitachi, Tokyo, Japan). The diameters of nerve fibers and axons were measured both longitudinally and axially, and the axes were averaged. Images were analyzed with the Imaging System KS 400 (Kontron Elektronik, Munchen, Germany).