Fig. 9

Immunostaining of connexin 45 in human testicular biopsy specimens. (A) In the tubule with normal spermatogenesis, the signal of the immunoreaction is clearly visible in the cytoplasm of Sertoli cells (white arrowheads) with the strongest signal intensity tending to be located in the basal half of the seminiferous epithelium. (B) In case of germ cell neoplasia in situ, the labelling is also attributed to the cytoplasm of Sertoli cells (white arrowheads), which are now located further adluminal. (C) Seminoma cells show a brown signal, which appears in spots rather than in lines, mainly at the boundaries to adjacent cells (arrows). Sertoli cells are not detectable anymore. (D) The wall of a blood vessel within a biopsy displaying normal spermatogenesis is clearly stained and can be interpreted as a positive control. (E) Within the seminiferous epithelium of an adult mouse with normal spermatogenesis, the cytoplasm of Sertoli cells is labelled (white arrowheads) as is the cytoplasm of Leydig cells (asterisk), which together additionally serves as a positive control. The sections treated with blocking peptide (inserts) as well as the representative negative control of a human normal spermatogenesis tubule (F) show no reaction. Scale bars = 20 μm (A–E), 50 μm (F; inserts)