At this older age, the numbers of apoptotic cells in stages IX-I and VII-VIII were significantly greater than the apoptotic frequency associated with stages II-VI (Table 1). The morphology of apoptotic type A spermatogonia in stages IX-I (Fig. 1G) and midpachytene spermatocytes in stages VII-VIII appeared to be identical to that of the corresponding cells in younger animals and were also shown to stain positively with the TUNEL procedure (Fig. 1, G and G’, and Table 1). Intermediate and type B spermatogonia were not seen to undergo death by apoptosis. generic paxil
At 60 days ofpostnatalage.In the mature rat testis, the number of TUNEL-positive, apoptotic cells per 1 ^m3 of tissue volume was lower than that observed in the immature 18- and 26-day-old testis (Table 1). The morphology of the different spermatogenic stages and stage-specific apoptosis in vital cell preparations derived from the mature rat testis have been described well in the literature and were therefore not examined here.
Electron-Microscopic Examination and Levels of Activated Caspase 3 and Cleaved PARP in the Maturing Rat Testis
At 8 days of postnatal age. At this early time-point, abundant procaspase 3 (Fig. 2A), but low levels of activated caspase 3 (Fig. 2B) and cleaved PARP (Fig. 2C), were detected. Electron microscopic examination confirmed the ap-optotic nature of spermatogonia and gonocyte death.
FIG. 2. Determination of the levels of (A) procaspase 3, (B) cleaved caspase 3, and (C) cleaved PARP in the immature rat testis during the first wave of spermatogenesis as well as in the mature testis by Western blot analysis. The upper strips illustrate the autoradiograms, and the bar graphs depict densitometric quantitation of the bands. The heights of the columns represent the mean densities, and the bars indicate the SEM. *P < 0.05 compared to the corresponding value for the 60-day-old testis, **p < 0.05 compared to the corresponding value for the 8-day-old testis.