Effect of different transport temperatures on in vitro maturation of oocytes collected from frozen-thawed sheep ovaries

Authors : Özen Banu ÖZDAŞ, Alper BARAN, Muzaffer TAŞ, Ümüt CİRİT, Kamber DEMİR, Süleyman BACINOĞLU, Serhat PABUCCUOĞLU, Kemal AK

Pages : 15-19

Doi:10.3906/sag-1208-44

View : 18 | Download : 6

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :The aim of this study was to determine the effects of 2 different transport temperatures on the in vitro maturation of oocytes collected from frozen-thawed sheep ovaries. Sheep ovaries were transferred into saline at temperatures of 4 °C and 32 °C. After the 2 experimental groups insert ignore into journalissuearticles values(A: fresh cortex, B: frozen-thawed cortex); were formed, each group was divided into 2 subgroups insert ignore into journalissuearticles values(group A1: 4 °C, group A2: 32 °C [control]; group B1: 4 °C, group B2: 32 °C);. The cortexes were dissected into slices 1-3 mm thick and pieces of 0.5 cm2. For groups B1 and B2, 1-2 cortex pieces were placed in cryogenic vials containing 1 mL of freezing medium modified with Earle`s salts insert ignore into journalissuearticles values(TCM-199); and supplemented with 10% fetal calf serum insert ignore into journalissuearticles values(FCS); insert ignore into journalissuearticles values(FCS + 2.5 M ethylene glycol + 0.1 M sucrose);. The vials were then cooled to -7 °C at 2 °C/min and held at -7 °C for 10 min for manual seeding. The temperature was then lowered by -0.3 °C/min to -35 °C and thereafter by -10 °C/min to -75 °C. Vials were plunged into -196 °C liquid nitrogen and stored. Cortexes were thawed at 37 °C. Collected oocytes were matured in their own groups in 700 µL of TCM-199 insert ignore into journalissuearticles values(supplemented with luteinizing hormone, follicle-stimulating hormone, pyruvate, and FCS); for 23 h in a gas mixture of 5% CO2, 5% O2, and 90% N2 at 38.8 °C. After maturation, oocytes were fixed in acetic acid and ethyl alcohol insert ignore into journalissuearticles values(1:3); for 48 h. Oocytes were stained with aceto-orcein and then examined. At the end of the study, maturation rates for reaching metaphase I insert ignore into journalissuearticles values(MI); were similar in all groups insert ignore into journalissuearticles values(group A1: 30.76%, group A2: 38.09%, group B1: 30.65%, and group B2: 33.33%);. The rates at which metaphase II insert ignore into journalissuearticles values(MII); was reached were 18.58%, 34.69%, 7.25%, and 6.48%, respectively. The best development was seen in group A2 insert ignore into journalissuearticles values(P < 0.001);. Sheep oocytes obtained from fresh and frozen-thawed cortexes reached the MII stage if transported at 4 °C.
Keywords : Key words Sheep, oocyte, maturation, ovary cortex, transport temperature