Figure 1

Spindle formation and chromosome alignment in oocytes. A, B, C, D, E and F showing spindles in green after staining with an anti α-tubulin antibody, and a, b, c, d, e and f showing chromosomes in blue after DAPI staining (chromatin). Normal bi-polar spindle and well-aligned chromosomes were present in MII oocytes (0 h) after 40–44 h entirely in culture (A and a), or in an oocyte 36 h post-hCG (B and b); asymmetric spindle and displaced chromosomes around the spindle equator plate in a MII oocyte after 40–44 h in culture (C and c); an oocyte retrieved at 36 h post-hCG was arrested at anaphase I (D and d); MI oocyte retrieved 36 h post-hCG possessed abnormal spindles and disorganised chromosomes (E and e); a cultured oocyte retrieved at 24 h post-hCG was arrested at GVBD with an abnormal spindle and disorganised chromosomes (F and f). Magnification bar in (A) = 5 μm