RESUMEN
To study the structure and distribution of microtubules in embryos derived from young, old and reconstructed oocytes. Embryos obtained from old [50 embryos], young [50 embryos] and reconstructed oocytes [10 embryos] were studied by immunocytochemistry. The microtubule structures of the embryos were studied by using fluroscent microscopy with FITC-PI filter and polyclonal antibody against alfa tubulin. The spindle structure of MII young oocyte and the obtained embryos were normal with the suitable condensation. There was no contact between chromosome and spindle in old Oocytes as well as the obtained embryos, in addition, the spindle was extended in old group. In reconstructed embryos, thin and scattered filaments were observed. This study reveals that the arrangement of microtubules in reconstructed embryos was caused by repeating of injection and oocyte manipulation. Also, interactions between karyoblast, cytoplasm and microtubuls may not be suitable. This may be caused by low fertilization in these oocytes