Fig. 5

Immunohistochemical analysis of blood-testis barrier proteins. Pictures a, c, and e show intact spermatogenesis (NSP) as control, pictures b, d, and f show spermatogonial arrest (patient’s left testis). a, b ZO-1 staining in NSP (a) revealed a clear cytoplasmic Sertoli cell staining. In contrast, in the sample showing spermatogonial arrest (b), ZO-1 staining was absent in a tubule showing spermatogonia alone (right tubule), but was present in an adjacent tubule with single remaining primary spermatocytes (lined arrowheads). c, d The same staining behavior was identified for claudin-11, where a regular staining was detectable in NSP (c) and in single tubules with remaining primary spermatocytes (lined arrowheads) (d, left tubule). But no staining was detected in tubules with spermatogonia only (d, right tubule). e, f A similar staining pattern was identified for CX43 staining in NSP (e) and in single tubules with remaining primary spermatocytes (lined arrowheads) (f, left tubule). No staining was detected in tubules with spermatogonia only (f, right tubule). AEC detection, bar 50 μm (inset bar 25 μm), inset as negative control without first antibody