Figure 2

Cell proliferation and apoptosis in the testicular area of the gonad. Testicular area of the gonad at different stages of the second RC immunostained with the anti-BrdU mAb (a-c) or labeled with TUNEL (d-f). At spermatogenesis (a), spermatogonia stem cells and primary spermatogonia and spermatocytes cysts proliferate. At post-spawning (b) and testicular involution (c) spermatogonia stem cells and primary spermatogonia cysts were inmunostained. Only at post-spawning (d) and testicular involution (e,f) were apoptotic cells observed. Notice that in the testicular peripheral area (e) the number of TUNEL positive cells is higher than in the testicular internal area (f). Scale bar = 25 μm (a-f). (arrowheads), proliferative cells; (arrows), TUNEL positive cells; Sg, Spermatogenesis; PS, post-spawning; TI, testicular involution; PTI, peripheral testicular area in the involution stage; ITI, internal testicular area in the involution stage.