The Effects of 5% Oxygen Condition and Superoxide Dismutase ( SOD ) on the in - vitro Development of Preimplantation Mouse Embryos / 대한산부인과학회잡지

OBJECTIVE: In the human body the embryo initially gmws in the fallopian tube which is maintained in an 3-8% O2 concentration environment, and various substances such as growth factors and antioxidants present in tbe tubal fluid assists in maintaining a healthy environment for embryo development. But in IVF programs embryo cultures are conducted in incubators with 21.9% O2 and 5% CO2 condition, and such high oxygen concentrations have been reported to increase the production of oxygen free radicals within the embryo and is detrimental to the growth and development of the embryo. The objective of this study, therefore, is to determine the culture conditions which will decrease oxygen free radical production and thereby minimize the injury to the embryo. METHODS: Six to eight week old ICR strain mice embryos were cultured in 5% or 21.9% O2 conditions and in culture media to which inaement concentrations of superoxide dismutase (SOD) had been and the H2O2 concentration within the embryo, embryo developmental rate, and degree of fragmentation of the embryos was investigated. RESULTS: The control gmup embryos which were cultured in 21.9% O2 condition without addition of SOD showed developmental arrest at the 2-cell stage or fragmentation, while those cultured in 21.9% O2 condition with addition of SOD showed development to the blastocyst stage with deaeased fragmentation. In particular, the blastulation and fragmentation rates were the lowest in the group to which 500 IU/ml of SOD was added, but in the 5% O2 enviranment group many embryos reached the blastocyst stage and with no difference in frapnentation with or without addition of SOD. The HO relative intensity (120.5+/-20.2) within the embryos cultured in 21.9% O2 environment without SOD was significantly higher than that (56.8+/-10.8) of group with SOD (p<0.05). As showing that in the 5% O2 environment group without SOD it was 43.8+/-7.8 and in the group with SOD it was 37.3+/-5.4, the H2O2 concentration within embryos cultured in 5% 02 condition was significantly lower those that of 21,9% 02 environment regardless of SOD addition (p<0.05). CONCLUSION: The optimal oxygen concentration in incubator for mice embryo cultures is that which is similar to the 5% 0 concentration in vivo. When 20% 02 incubators are routinely used, the addition of SOD to the culture media will decrease the H2O2 concentration within the embryos with subsequent improvement in development. The optimal concentration which should be used is thought to be 500 IU/ml. It is suggested that the use of the above method in human IVF-ET programs will lead to improved embryo quality and enhanced pregnancy rates.

Effects of Low Oxygen Condition on the Development of Mouse Embryos Cultured In Viro / 대한산부인과학회잡지

OBJECTIVE: It is known that mouse embryos before implantation develop in a low oxygen environment of 3- 8% concentration and with antioxidant materials such as vitamins, antioxidant enzymes, ferrous binding proteins, and albumin in follicular and tubal fluids. However, the 20% oxygen culture condition with chemically defined media might be produce an abundance of ROS, and leads to developmental delay or developmental block in vitro. In this study, we attempt to elucidate the relationship between intracellular H2O2 production and embryo development in different oxygen culture conditions of mouse embryos. METHODS: Prenuclear embryos from C57BL/CBA Fl hybrid and ICR mouse were cultured in incubators which provided 5% carbon dioxide, 20% oxygen and 5% carbon dioxide, 5% oxygen. Measurement of H2O2 level in a embryo was performed with DCHFDA(2, 7 -dichlorodihydroflourescein diacetate)and analyzed with Quanti-cell 700, and the number of blastomeres was counted with DAPI( 4, 6'-diamidino-2-phenylindole). RESULTS: Oxygen concentration of the culture medias was significantly higher in the 20% oxygen environment compared to that of 5% oxygen environment. Culture of mice embryos in high oxygen condition leads to high HO concentrations at 2 cell stage and developmental delay or ""2-cell block"" regardless of the strain. But in a 5% oxygen environment, which is similar to in-vivo conditions HO production was suppressed continuously through out culture and development of embryos was definitely improved. CONCLUSION: These results suggest that there is a difference in the production of ROS or protective mechanism according to the mouse strains and stage of development, and it is thought that in-vitro culture in 5% oxygen environment provides stable in vivo equilibrium but in a 20% oxygen environment there is production of ROS which overcome the protective mechanism which leads to cellular damage and embryo developmental delay.

Cyclic Expression of Cyclooxygenase-1 and -2 in Human Endometrium / 대한불임학회지

Cyclooxygenase (COX) is an enzyme involved in the conversion of arachidonic acid to prostaglandins(PGs), and exists in two forms, COX-1 and COX-2. COX has been reported to be involved in early implantation by secretion of PGs which causes permeability of vessels and reaction of decidual cells around the implantation site. Recently, in mice and sheep studies, COX-1 and COX-2 expression in the endometrium has been reported to be different according to implantation and stages of the estrous cycle, but expression of COX-1 and COX-2 in human endometrium during the menstrual cycle has not yet been established. The purpose of this stuffy was to observe the variances of COX-1 and COX-2 expression by immunohistoehemical staining in endometrial samples obtained from human hysterectomy specimens and biopsies of women of reproductive age according to different stages of the menstrual cycle. Also, we attempted to observe COX-1 and COX-2 expression in the epithelial and stromal cells of the endometrium obtained during the mid-secretory phase, which were cultured separately. COX-2 showed a cyclic pattern of expression according to the different stages of the menstrual cycle and was strongly expressed particularly at the mid-secretory phase which corresponds to the time of implantation. However, COX-1 tended to be increased in the early proliferative, and mid- and late secretory phases, but was also expressed in the whole menstrual cycle showing no particular pattern. In the separately cultured cells COX-1 was expressed in epithilial cells and COX-2 in the stromal cells. The above results suggest that since COX-2 is expressed at the same time as implantation and cultured cells display a specific secretory pattern, COX-2 has inductive endocrine enzyme properties and has an important effect on endometrial cells during implantation. Also, COX-2 expression in endometrial cells may be utilized as a useful marker of endometrial maturation.

Significance of Color Doppler Sonography in the Conservative Therapy of Adnexal Torsion / 대한산부인과학회잡지

Torsion of the adnexa is a well-known gynecologic cause of an acute surgical abdomen. Delay in diagnosis, inability to distinguish strangulation from necrosis, and fear of embolus dislodgement have made adnexectomy the accepted method of management of adnexal torsion. This condition occurs most commonly in the reproductive years, yet methods to preserve viable ovarian tissue have not been routinely used or evaluated. Therefore, in order to ascertain if color Doppler sonography(CDS) can detect adnexal viability, ultrasonography with CDS of the ovarian pedicle was performed in 27 patients in whom torsion of the ovarian tumor was confirmed surgically. We were able to identify a twisted vascular pedicle of the ovarian tumor by ultrasonography in 24 of 27 patients(88% detectability). In 10 patients in which pedicle arterial and venous blood flow was observed, the pathology specimens revealed normal, or edema with congestion, or early hemorrhage, but in the 9 cases where only arterial blood flow was observed or where there was no blood flow at all, pathology revealed hemorrhagic necrosis in all cases. In 5 cases where there was arterial blood flow the tumor was managed conservatively, either by detorsion or cytectomy, after which there was no cases of embolism or tumor recurrence during follow up ultrasonography. Normal follicular development and ovulation was also observed in these patients. In conclusion, for young women who are of child-bearing age in whom torsion of benign adnexal tumors is suspected, CDS should be conducted to detect torsion of the tumor and ascertain whether pedicle venous blood flow is present or not. If such blood flow is detected, the adnexa is considered to be viable and detorsion or cystectomy may be performed, thus preserving the ovary.