Fixation of testicular tissue for immunohistochemical and ultrastructural examination

The fixation of testicular tissue with glutardialdehyde destroys the antigenicity of cell epitopes in many cases. To obtain both, morphological and immunohistochemical examination, a fixation which could preserve the antigenicity and condition of the testicular structure was sought. The solution obtained was a mixture of 3.7% formalin with 0.2% glutardialdehyde and 0.05% saponin in a phosphate buffer of pH 7.4. Blocks of human tests were immersed in this fixative, embedded in Epon 812 or paraffin for conventional light and electron microscopy and immunohistochemical staining. The immunohistochemical examination was focused on the lamina propria of the human seminiferous tubules. Good preservation of the structure was observed both in light and electron microscopy. Cytological details were seen by light microscopy, especially the recognition of single tumour cells. Electron microscopically, all cells of the seminiferous tubules and the lamina propria showed a well-preserved internal structure. At the same time the peritubular cells of the lamina propria exhibited a well-expressed vimentin and desmin immunoreactivity, thus providing evidence that the corresponding epitopes retain their antigenicity under these fixation conditions. The applied fixation procedure provides comparable results in preservation of the structure to glutardialdehyde but does not destroy the antigenicity of epitopes.