Fig. 3.

Spermatid abnormalities and death during Vps13b^{∆Ex3/∆Ex3} spermiogenesis. a Representative haematoxylin/eosin-stained sections of wild-type and Vps13b^{∆Ex3/∆Ex3} seminiferous tubules at stages II–III, V–VII, and X–XII. Nuclei of late spermatids failed to elongate during acrosome and maturation phases (arrows). Se sertoli cell, Spg spermatogonia, Spc spermatocyte, Spd(E) early spermatid, Spd(L) late spermatid, M meiosis metaphase II. Scale bars 50 µm. b Quantification of spermatid numbers in seminiferous tubules from spermatid stages 1–16 (N = 15 tubules per stage and per genotype; 5 mice per genotype were used and 3 tubules per stage and per mouse were counted). Spermatids were divided into five groups: stages 1–4, 5–8, 9–12, 13, 14, and 15, 16. From stage 9 onward, spermatids were significantly fewer in tubules of Vps13b^{∆Ex3/∆Ex3} mice than wild-type mice [p(9–12) = 0.004; p(13–14) < 0.001; p(15–16) < 0.001]. All values are presented as the mean ± SD. Significance was determined using Welch two sample t test. c Representative images of TUNEL staining on a Vps13b^{∆Ex3/∆Ex3} seminiferous tubule section at stages V–VII. Scale bars 50 µm. d Quantification of TUNEL-positive spermatids in stage groups 1–8, 9–12, and 13–16 (N = 21 tubules per stage and per genotype; 7 mice per genotype were used and 3 tubules per stage and per mouse were counted). Mutant sections showed significantly more TUNEL-positive spermatids, especially from stages 9 to 16 [p(1–8) = 0.03; p(9–12) = 0.002; p(13–16) = 0.002]. All values are presented as the mean ± SD. Significances were determined using Wilcoxon rank sum test