149 EFFECT OF RESVERATROL ANALOGUE ON DEVELOPMENT OF IN VITRO-FERTILIZED BOVINE EMBRYOS

Abstract

Oxidative stress is one of the main effects of in vitro culture. Generation of reactive oxygen species (ROS) by embryos can be enhanced by the sub-optimal in vitro culture conditions and are associated with a delay in embryonic development. However, supplementation of culture medium with antioxidant agents can minimize the effects of ROS (Guérin et al. 2001 Hum. Reprod. Update 7, 175–189). Resveratrol is an example of a potent antioxidant, and modifications in its structure can improve its biological activity. This study evaluated the effect of AR33 (formula with patent pending), an analogue of resveratrol with high antioxidant activity, on embryo development. Bovine cumulus-oocyte complexes recovered from ovaries collected at the slaughterhouse were in vitro matured for 24 h and oocytes were in vitro fertilized for 20 h, both at 38.8°C under 5% CO₂ in air and high humidity. Partially denuded presumptive zygotes were randomly distributed in 4 treatments (with 6 replicates): 0 µM (control, n = 347), 0.1 µM (n = 337), 0.5 µM (n = 277), and 2.5 µM (n = 343) of AR33. The base medium was SOFaa supplemented with 2.5% FCS and incubation conditions were 38.8°C under 5% CO₂ in air and high humidity. Half of culture medium was renewed (feeding) at Day 3 and 5 post-fertilization. Cleavage was evaluated at Day 3 and blastocyst rates at Day 7 and 8 post-fertilization. Data were analysed by logistic regression considering the significance level of P < 0.05. Values are shown as mean ± SEM. Cleavage rate was higher (P < 0.05) for 2.5 µM (69.0 ± 4.4%) than for 0, 0.1, and 0.5 µM AR33 (62.1 ± 2.0%, 60.7 ± 5.9%, and 56.7 ± 5.8%, respectively). At Day 7, the blastocyst rate was similar (P > 0.05) among 0.1, 0.5, and 2.5 µM (18.1 ± 5.4%, 17.5 ± 2.9%, and 19.4 ± 3.3%, respectively) and all of them were higher (P < 0.05) than 0 µM AR33 (12.4 ± 2.5%). At Day 8, there was again no difference (P > 0.05) among 0.1, 0.5, and 2.5 µM AR33 (21.0 ± 5.0%, 18.4 ± 2.1%, and 24.6 ± 3.3%, respectively) but only 0.1 and 2.5 µM showed higher (P < 0.05) blastocyst rate than 0 µM AR33 (15.2 ± 2.5%). In conclusion, the synthetic analogue of resveratrol tested in this study can improve bovine embryo development in culture medium supplemented with 2.5% FCS under 5% CO₂ in air. A concentration of 2.5 µM AR33 can be a choice for further studies.

This study was supported by Fapemig, CAPES, and CNPq.