RESUMEN
<p><b>OBJECTIVE</b>To evaluate the morphology and proliferation of follicles from cryopreserved human ovarian tissue by vitrification.</p><p><b>METHODS</b>Ovarian biopsy specimens were taken from 12 patients. The specimens were randomly distributed into fresh group (Group A) and vitrification group (Group B). Histological examination and ultrastructural observation were performed after cryopreservation. Both were embedded in paraffin block and proliferating cell nuclear antigen (PCNA) was detected by immunohistochemical staining.</p><p><b>RESULTS</b>The proportions of primordial and primary follicles from Group A and Group B were 86.4%, 13.6% and 84.5%, 15.5%, respectively (P>0.05). There was no significant difference in proportions of morphologically normal primordial follicles between Group A and Group B (P>0.05); but the proportion of morphologically abnormal primary follicles was significantly higher in Group B than that in Group A (P<0.05). The ultrastructural studies showed that in histologically normal primordial follicles, there was no difference between Group A and Group B, while there were a few abnormalities of primary follicles in Group B. Granulosa cells and oocytes of primordial and primary follicles and stromal cells were positive for PCNA staining both in fresh and cryopreserved ovarian tissues; there were no differences between two groups.</p><p><b>CONCLUSION</b>Vitrification is a favorable method in human ovarian cryopreservation.</p>