EFFECT OF OXIDATIVE STRESS ON DEVELOPMENT OF IN VITRO PRODUCED CAMEL EMBRYOS

The aim of the present study was to evaluate the effect of supplementation of ascorbic acid (first experiment), cysteine (second experiment) and combination of both antioxidants (third experiment) to in vitro culture (IVC) medium on the development of dromedary camel embryos and expression profile of candidate genes regulating embryo quality. Cumulus-oocyte complexes (COCs) were recovered from camel ovaries collected from local abattoir. Good quality COCs were used in the standard protocol of in vitro embryo production including in vitro maturation (IVM) and in vitro fertilization (IVF). The presumptive zygotes were incubated in culture medium with/without antioxidant according to the experiment. First experiment: The presumptive zygotes were allocated into four treatments of ascorbic acid, namely; control group (T1), 50 μg/ml (T2), 100 μg/ml (T3) and 150 μg/ml of ascorbic acid (T4). In the second experiment: three cysteine concentrations (T2: 100 µM, T3: 500 µM and T4: 1 mM) were supplemented to IVC medium and compared with control group (T1). The third experiment consisted of four experimental groups; control group without antioxidant (T1), 150 μg/ml ascorbic acid (T2), 100 µM cysteine (T3) and a combination of 150 μg/ml ascorbic acid and 100 µM cysteine (T4). The relative abundance of b-cell lymphoma 2 (BCL2), catalase (CAT), superoxide dismutase (SOD), glucose transporter 1 (GLUT-1), thioredoxin (TXN) and tumor suppressor protein (P53) genes were assessed using real-time PCR. All experimental groups were incubated in 5% CO2, 20% O2 and moist atmosphere at 38.5 ◦C for 6 days. In the first experiment, results showed that all groups supplemented with ascorbic acid (T2, T3 and T4) were significantly higher in blastocyst rate compared to the control group (10%, 16.67%, 25% and 2.04%, respectively). Meanwhile, no significant difference was observed among ascorbic acid treatments. In the second experiment: supplementing IVC medium of dromedary camel embryos with cysteine was found to have a positive significant ...