The aim of the present study was to test the effect of the interval of seri
al sections in the tissue chopper on the number of isolated ovine preantral
follicles. Best results were obtained when the ovarian fragments were cut
in the tissue chopper at interval of 87.5 mu m (1592 preantral follicles pe
r treatment). Histochemical analysis showed that the follicular morphology
was preserved after mechanical isolation as demonstrated by the normality o
f oocytes and granulosa cells as well as by preservation of basement membra
ne. The percentages of isolated primordial, primary and secondary follicles
were 92, 6, and 2%, respectively. The follicular sizes varied from 12.5 to
96.3 mu m in diameter. In conclusion, a greater number of isolated preantr
al follicles were obtained when the method of isolation used the tissue cho
pper adjusted at 87.5 mu m. Besides, this treatment does not affect the fol
licular integrity after the isolation procedure. (C) 2000 Elsevier Science
B.V. All rights reserved.