Transmission Electron Microscopy
For ultrastructural studies testes were harvested from 32-week-old male mice and fixed overnight at 4°C in a solution consisting of 2% gluteraldehyde, 2.5% paraformaldehyde and 0.06% picric acid in 0.2M sodium cacodylate buffer (pH7.4). Fixed specimens were washed with cacodylate buffer, post-fixed in osmium tetroxide, dehydrated in graded ethanol and embedded in epoxy resin. Semithin sections were cut at approximately 0.35 μm and stained with toluidine blue and basic fuchsin and examined by light microscopy for regions of interest. Ultrathin sections (90 nm) were stained with uranyl acetate and lead citrate and examined with a Tecnai G2 Spirit BioTWIN transmission electron scope equipped with an AMT 2k CCD camera.