Figure 5
From: Usp26 mutation in mice leads to defective spermatogenesis depending on genetic background
Apoptosis of germ cells in Usp26 mutant mice. (A) TUNEL analysis of Usp26 mutant testes. Apoptotic cells were detected with TUNEL assays (green) and the nuclei were stained with DAPI (blue). Asterisk represents seminiferous tubules containing TUNEL–positive cells. The mice backcrossed to a DBA/2 background 5 generations were used in Fig. 5A–D. Bars: 100 µm. (B) Average number of TUNEL–positive cells per tubule. More than 140 tubules were analyzed per mouse. Mutant mice exhibited a greater number of apoptotic cells (Student’s t-test; *P < 0.05). The mean ± standard deviation is shown. (C) The number of TUNEL–positive cells per stage XII tubule. The number of TUNEL–positive cells in the individual tubules were plotted and the values for each mouse are represented in different colors. The number of TUNEL–positive cells was significantly elevated in mutant mice (Student’s t-test; *P < 10−4); the mean ± standard deviation is shown. (D)Apoptotic cells in meiotic division in stage XII–I tubules in Usp26 mutant mice. Arrows indicate TUNEL–positive metaphase spermatocytes. Bar: 5 µm. (E) Toluidine blue-stained stage XII–I seminiferous tubules of wild-type (transverse section) and Usp26 mutant mice (longitudinal section). There was an accumulation of degenerated spermatids detached from the epithelial layer within the lumen of stage XII–I tubules in Usp26 mutant mice (enclosed with red dotted line). The mice backcrossed to a DBA/2 background 4 generations were used. P, meiotic figure of the primary spermatocyte; E, seminiferous epithelium; L, lumen. Bar: 10 µm.
