Figure 7

Figure 7. Effects of Gdnf on germ cell composition and cellular proliferation, using a previously established primary testis tissue culture system. (A,B) BrdU immunodetection from zebrafish testicular explants incubated for 7 days in the absence (Basal) or presence of rhGDNF (100 ng/mL), demonstrating a higher proliferation activity for type A undifferentiated spermatogonia (A_und) and type A differentiated spermatogonia (A_diff) in the presence of rhGDNF. (C) Frequency of different germ cell cysts after 7 days of incubation in the absence (Basal) or presence of rhGDNF (100 ng/mL). Types A_und, A_diff and B spermatogonia (SPG B), spermatocytes (SPCs) and spermatids (SPTs) were identified according to morphological characteristics, as described by Leal and collaborators [55]. (D) Mitotic indices of type A_und and A_diff spermatogonia after incubation in the absence (Basal) or presence of rhGDNF (100 ng/mL) for 7 days. (E) Mitotic indices of Sertoli cells in association with BrdU-negative or BrdU-positive type A_und and A_diff spermatogonia in the absence (Basal) or presence of rhGDNF (100 ng/mL) for 7 days. Sertoli cells were identified according to morphological characteristics, as described previously [55]. In fish, Sertoli cells (SCs) have a triangular nuclear shape, dark chromatin and usually they appear surrounding spermatogenic cysts, as shown in Figure S1. Bars represent the mean ± SEM (n = 10). Paired t-test, * p < 0.05, ** p < 0.01, *** p < 0.001. Scale bars: 15 µm.