Retinoic acid improves maturation rate and upregulates the expression of antioxidant-related genes inin vitromatured buffalo (Bubalus bubalis) oocytes

Abstract

Retinoic acid, vitamin A metabolite, plays a role in oocyte development and maturation in different ways including gene expression alteration and/or prohibiting oxidative stress. The objective of this study was to examine the effect of 9-cis-retinoic acid (9-cisRA) on the quality and maturation rate of buffalo oocytes. Cumulus-oocyte complexes (COCs, n = 460) were collected from ovaries of slaughtered buffalos. Varying concentrations of 9-cisRA (0, 5, 50, and 200 nM) were added to the maturation medium, and the following parameters were analyzed: (i) maturation and cleavage rates, (ii) mitochondrial activity and reactive oxygen species (ROS) levels, (iii) expression level of antioxidant-related genes (PRDX1, SOD1, CAT, HOMX1, and GPX4) using RT-qPCR. Maturation rate was significantly improved in 5 nM 9-cisRA oocyte group (95.8%, P < .05) compared to control and other treatment groups (86.7% in control group). The same oocyte group exhibited significantly higher mitochondrial membrane potential activity and lower ROS accumulation level compared to other treatment groups. Antioxidant-related genes were up-regulated in oocytes matured with 5 or 50 nM 9-cisRA compared to control and 200 nM 9-cisRA groups. In contrast, 200 nM of 9-cisRA showed a clear down-regulation for antioxidant-related genes except for PRDX1. In conclusion, supplementation of 9-cisRA with a lower concentration (5 nM) to the buffalo oocytes maturation media promotes maturation rate through a protection mechanism that maintains adequate levels of antioxidant-related transcripts and improves mitochondrial activity. However, 9-cisRA has no significant effect on the cleavage rate of the treated oocytes.

The Usefulness of Retinoic Acid Supplementation during in Vitro Oocyte Maturation for the in Vitro Embryo Production of Livestock: A Review

“…Within the ovarian tissue, both CRBP and RBP are expressed in the granulosa and theca cells and control the movement of retinol from the blood to the growing ovarian follicles [10]. Levels of RBP and its substance retinol in the follicular fluid of large pre-ovulatory bovine ovarian follicles were found to be higher than in the atretic or smaller ovarian follicles [4].…”

“…In water buffaloes, Gad et al [4] found that supplementation with 5 nM of 9-cisRA to the in vitro maturation medium led to a higher oocyte maturation rate. Moreover, treatment with high levels of RA (50 and 200 nM) throughout the maturation stage revealed the minimum maturation (26.43%) and polar body rates (23.6%).…”

“…Moreover, treatment with high levels of RA (50 and 200 nM) throughout the maturation stage revealed the minimum maturation (26.43%) and polar body rates (23.6%). Moreover, the addition of 9-cisRA at a level of 5 nM significantly increased the cytoplasmic and nuclear growth in buffalo oocytes [4]. Accumulating evidence suggests that RA might have favorable or detrimental influences during oocyte maturation and embryo development in most livestock species.…”

“…Providing essential nutrients or survival factors to the maturation media has become a broadly applicable approach; this may have the advantages of enhancing in vitro oocyte competence and embryonic growth. In light of this, many approaches have been implemented to explore the impacts of different culture conditions enriched with antioxidants or vitamins on oocyte ripening and embryonic growth in different mammalian species [1,4,5,6,7]. The low efficiency of in vitro embryo production could be attributed to the lack of knowledge on different nutritional requirements for oocyte maturation and embryo development, ROS generation, the difference in time of cytoplasmic and nuclear maturation, the inferior characters of frozen semen, apoptosis, and/or the alteration of transcription gene expression [4,5,7].…”

Effect of Season and Ovarian Morphology of Egyptian Buffalo on Oocyte Quality and In Vitro Maturation Rate

“…The oocyte quality can be assessed by their ability to mature, fertilize and produce blastocyst (Hussein et al, 2006). Recently, the quality of oocytes and in vitro embryo production (IVEP) can be increased in river buffaloes by superstimulation of follicular activity by FSH followed by GnRH (Sakaguchi et al, 2019) or addition of Retinoic acid (vitamin A metabolite) to the media increased gene expression, maturation and decrease the ROS (Gad et al, 2018). The ovarian structures, morphology and CL are still requiring more investigation and study for improvement of oocyte quality and in vitro maturation in buffalo (Singh and Adams, 2000).…”