Capability of oocyte maturation in human cryopreserved ovarian tissue following xenografting / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the development and maturation competence of oocytes retrieved from cryopreserved and transplanted human fetal ovarian tissue by techniques of tissue culture, inducing ovary, oocyte retrieval, and in vitro maturation (IVM).</p><p><b>METHODS</b>Fetal ovaries of 20 weeks were frozen-thawed and cultured for 6 days in vitro, then xenografted into kidney capsules of immunodeficient mice. All mice were stimulated with follicle stimulating hormone every second day for 23 weeks, starting 1 week after grafting. Then oocytes were retrieved from antral follicles 13 hours after human chorionic gonadotrophin injection. IVM was performed to evaluate the maturation competence of the oocytes from ovarian grafts. Human fetal ovarian tissues were examined with histological and proliferating cell nuclear antigen (PCNA) evaluation.</p><p><b>RESULTS</b>There was no difference between fresh ovarian tissues and frozen-thawed ovarian tissues in the percentage of follicles at different growth stages (P > 0.05). The proportion of the primary follicles and preantral follicles in the cultured ovarian tissues was significantly larger than that of fresh ovarian tissues and frozen-thawed ovarian tissues (P < 0.05). The proportion of the primary follicles, preantral follicles, and antral follicles in the transplanted ovarian tissues was significantly higher than that of cultured ovarian tissues, fresh ovarian tissues, and frozen-thawed ovarian tissues (P < 0.05). No significant signals of PCNA in the primordial follicles in all ovarian tissues were observed. PCNA immunoreactivity first appeared in primary follicles. However, the obviously positive signals of PCNA were seen in the oocytes and/or the granular cells of cultured ovarian tissues and transplanted ovarian tissues. Oocytes from antral follicles were collected and matured in vitro, and 21.43% of the oocytes reached to MII within 48 hours IVM.</p><p><b>CONCLUSIONS</b>Human ovarian follicles can survive and develop well after cryopreservation, tissue culture, and xenotransplantation. Furthermore, oocytes recovered from grafts have normal maturation competence.</p>

Reversal of multidrug resistance of tumor cells by anti-mdr1 ribozyme / 中华病理学杂志

<p><b>OBJECTIVE</b>To stably reverse the multidrug resistance (MDR) of breast carcinoma cells in vitro.</p><p><b>METHODS</b>Two anti-mdr-1 ribozyme plasmids, RZ196 and RZ179, were constructed with EGFP as reporter gene and transfected into drug-resistant breast carcinoma cells in vitro. The expression of EGFP was observed by laser confocal microscopy. Flow cytometry, RT-PCR and Rhodamine123 efflux assay were used to detect P-glyco protein (p-gp) and mdr-1 mRNA.</p><p><b>RESULTS</b>After transfection with RZ196 and RZ179, the mdr-1 indices were reduced from 2.20 to 0.76 and 1.40, the expression rates of p-gp were reduced from 55.0% to 4.6% and 18.2%, the fluorescence intensity increased from 22.0% to 46.2% and 70.1%, TCL reduced from 75% to 28% and 43% respectively. In addition, the expression of ribozyme plasmid in tumor cells was stable under G418 selection. After two months, the mdr-1 indices remained at 0.81 and 1.47 in the cells transfected RZ196 and RZ179 respectively. The expression rates of p-gp were 5.2% and 19.5% and the Rh123 fluorescence intensity was 51.4% and 71.6% respectively.</p><p><b>CONCLUSIONS</b>Both anti-mdr-1 ribozyme RZ196 and RZ179 can stably reverse MDR phenotype of breast carcinoma cells in vitro. RZ196 construct appears to be more effective.</p>