Supplementation of L-carnitine during in vitro maturation of mouse oocytes affects expression of genes involved in oocyte and embryo competence:An experimental study

Abstract

Background:Oocyte developmental competence is one of the key factors for determining the success rate of assisted reproductive technique.Objective:The aim of the current study was to investigate the effect of L-carnitine (LC) supplementation during in vitro maturation (IVM), on preimplantation embryo development and expression of genes involved in embryo competence derived from oocytes selected with brilliant cresyl blue (BCB) test.Materials and Methods:Cumulus-oocyte complexes (COCs) were obtained from NMRI mice ovaries. COCs were stained with BCB and then BCB+ (colored cytoplasm) oocytes cultured in IVM medium supplemented with 0.3 or 0.6 mg/ml LC. COCs untreated with LC were used as control. Fertilization rate and blastocyst development rate were determined after in vitro fertilization. In addition, quantitative reverse transcriptase polymerase chain reaction was used to measure relative genes expression related with development (Ccnb1, Mos, Ces5, and Dppa2) and apoptosis (Bax and Bcl-xL) in oocytes and embryos.Results: Oocytes treated with both LC concentrations showed higher blastocyst development rate compared with untreated oocytes (p<0.01). Moreover, fertilization rate was increased in oocytes treated with 0.6 mg/ml LC (p<0.01). Treatment of oocytes with both LC concentrations increased (p<0.01) the level of Ccnb1 mRNA in MII oocytes. The two-cell stage embryos and blastocysts derived from LC-treated oocytes (0.6 mg/ml) showed increased the expression levels of Dppa2 and Bcl-xl mRNA, respectively (p<0.01).Conclusion: The results of the present study show that adding of LC to the IVM medium of BCB+ oocytes can ameliorate reproductive success following in vitro fertilization.

Regulatory Functions of L-Carnitine, Acetyl, and Propionyl L-Carnitine in a PCOS Mouse Model: Focus on Antioxidant/Antiglycative Molecular Pathways in the Ovarian Microenvironment

“…Proper energy supply is an essential condition for assuring correct spindle assembly and chromosome separation during meiosis [43]. In this respect fatty acid oxidation represents an important energy source for the oocyte as evidenced by the observation that it is increased by LC exposure of COCs during in vitro maturation and in vitro follicle culture in association with improved oocyte competence [44,45]. A further evidence for the relevance of this mitochondrial energy pathway is the observation that carnitine palmitoyltransferase-II (CPT-II) expression in mouse oocytes has been correlated with oocyte developmental competence.…”

Niacin improves maturation and cryo-tolerance of bovine in vitro matured oocytes: An experimental study

“…To evaluate the effects of niacin on cleavage rate and embryo development, a total of 677 oocytes were divided into four groups: (1) culture in IVM medium that was not vitrified (CG, n= 182); (2) culture in IVM medium with 400 µ M niacin that was not vitrified (CN, n= 177); (3) culture in IVM medium that was vitrified (CV, n= 158); and (4) culture in IVM medium with 400 µ M niacin that was vitrified (NV, n=160). Following maturation, oocytes were transferred into 500µl of fertilization medium (modified Tyrode’s medium) in four-well dishes (Nunc™, Denmark) (50 COCs/well).…”

“…The deficiency of antioxidant capacity within follicle has shown to decrease the maturation competency of the oocyte and, therefore, interfere in the process of fertilization and development (2,3). Enzymatic antioxidants such as catalase (CAT), superoxide dismutase (SOD), and the level of non-enzymatic antioxidants including L-carnitine, cysteamine, cysteine, and N-acetyl-L-cysteine, have been used to solve this problem (4,5). `` Nicotinic acid (niacin) is a lipid-modifying agent that decreases plasma triglyceride and low-density lipoprotein while raising high-density lipoproteins" (6).…”

Treatment of mouse cumulus‐oocyte complexes with L‐carnitine during vitrification and in vitro maturation affects maturation and embryonic developmental rate after parthenogenetic activation

“…L‐carnitine is an essential metabolite for glucose metabolism and energy production and increases mitochondrial metabolism and ATP production in cells (Yano et al, 2010). On the other hand, treatment of BCB + oocytes with LC has increased the blastocyst development rate after in vitro fertilization (IVF) via enhanced the expression of genes involved in embryonic development (Zare et al, 2017). Literature reports on the effects of LC treatment on cryotolerance of oocytes and embryos are inconsistent, with authors showing positive effects (Moawad et al, 2013; Truong & Gardner, 2020) or no effect (Carrillo‐González et al, 2020; Saraiva et al, 2018).…”