Search Results

1.Effects of Melatonin on the Meiotic Maturation of Mouse Oocytes in vitro.

Korean Journal of Fertility and Sterility 2004;31(3):155-168

OBJECTIVE: Melatonin, which is secreted by pineal gland play an important role in the regulation of ovarian function via seasonal rhythm and sleep in most mammals. It also has a role in the protection of cells by removing toxic oxygen free radicals brought about by metabolism. In the present study, effects of melatonin on the mouse oocyte maturation were examined using two different culture conditions provided with 5% or 21% oxygen concentration. MATERIAL AND METHOD: Immature mouse oocytes were obtained from the ovarian follicles of 3~4 weeks old ICR strain mice intraperitoneally injected with 5 I.U. PMSG 44 hour before. Under stereomicroscope, morphologically healthy oocytes with distinct germinal vesicle (GV) were liberated from the graafian follicles and collected using mouth-controlled micropipette. They were then cultured for 17 hour at 37degrees C, 5% CO2 and 21% O2 (95% air) or 5% CO2, 5% O2 and 90% N2. New modified Hank's balanced salt solution (New MHBS) was used as a culture medium throughout the experiments. Effects of melatonin were examined at a concentration of 0.0001 micrometer, 0.01 micrometer or 1.0 micrometer. For the prevention of spontaneous maturation of immature oocytes during culture, dibutyryl cyclic AMP (dbcAMP) and/or hypoxanthine were included in the medium. RESULTS: Under 21% oxygen condition, oocytes cultured in the presence of 0.01 micrometer melatonin showed a significantly higher maturation rates, in terms of germinal vesicle breakdown (95.0% vs 89.0%) and polar body formation (88.1% vs 75.4%), compared to those cultured with 0.0001 micrometer or 1.0 micrometer melatonin. However, no difference was observed in oocytes cultured under 5% oxygen whether they were treated with melatonin or not. In the presence of 0.01 micrometer melatonin, oocytes either cultured under 21% or 5% oxygen exhibited no difference in the polar body formation (85.6% vs 86.7%). However, in the absence of melatonin, oocytes cultured under 21% oxygen exhibited lower polar body formation (74.7%). When oocytes were cultured in the presence of dbcAMP alone or with varying concentrations of melatonin, those treated with both compounds always showed better maturation, i.e., germinal vesicle breakdown and polar body formation, compared to those cultured with dbcAMP alone. At the same concentration of melatonin, however, oocytes exposed to 21% oxygen showed poor maturation than those to 5% oxygen. Similar results were obtained from the experiments using hypoxanthine instead of dbcAMP. CONCLUSION: Based upon these results, it is suggested that melatonin could enhance the meiotic maturation of mouse oocytes under 21% oxygen concentration, and release oocytes from the meiotic arrest by dbcAMP or hypoxanthine regardless of the concentration of oxygen, probably via the removal of oxygen free radicals.
Animals ; Bucladesine ; Female ; Free Radicals ; Hypoxanthine ; Mammals ; Melatonin* ; Metabolism ; Mice* ; Oocytes* ; Ovarian Follicle ; Oxygen ; Pineal Gland ; Polar Bodies ; Seasons

PURPOSE: A wide variety of surgical materials have been used for blepharoptosis such as catgut, silicone, 4-0 nylon polyfilament cable-type ophthalmic suture (Supramid(R)), autogenous tendon (palmaris longus),banked sclera, dura mater, fascia lata, and temporalis fascia. The aim of this study was to evaluate the effect of frontalis suspensory surgery with temporalis fascia. METHODS: The authors studied 91 frontalis slings (71 patients) performed from 1993 to 1999 at our hospital for repair of blepharoptosis. Results with temporalis fascia (group A) as the suspensory material were compared to those with autogenous (group B) and preserved (group C) fascia lata. RESULTS: The success rates of group A (31 lids 21 patients), group B (28 lids 24 patients), group C (32lids 26 patients) were 80.6%, 75%, 78.1% respectively. But there was no statistically significant difference in each groups (P>0.05). CONCLUSIONS: We concluded that temporalis fascia for frontalis sling could be used as suspensory material successfully. Moreover, long term and further evaluations must be considered.
Blepharoptosis ; Catgut ; Dura Mater ; Fascia Lata ; Fascia* ; Nylons ; Sclera ; Silicones ; Sutures ; Tendons