<span style="font-variant: small-caps">l</span>-Carnitine Supplementation during In Vitro Maturation and In Vitro Culture Does not Affect the Survival Rates after Vitrification and Warming but Alters <i>Inf-T</i> and <i>ptgs2</i> Gene Expression

• Main Authors: Diego F. Carrillo-González, Nélida Rodríguez-Osorio, Charles R. Long, Neil A. Vásquez-Araque, Juan G. Maldonado-Estrada
• Format: Article
• Language: English
• Published: MDPI AG 2020-08-01
• Series: International Journal of Molecular Sciences
• Subjects: bovine embryo; cryotolerance; lipid metabolism; gene expression
• Online Access: https://www.mdpi.com/1422-0067/21/16/5601
• ISSN: 1661-6596; 1422-0067

<span style="font-variant: small-caps;">l</span>-carnitine is a potent antioxidant used for in vitro culture systems. Controversial results have been reported using <span style="font-variant: small-caps;">l</span>-carnitine in culture medium at different stages of in vitro bovine embryo production. Cumulus-oocyte complexes (<i>n</i> = 843) were in vitro-fertilized and cultured and added (treatment group) or not added (control group) with <span style="font-variant: small-caps;">l</span>-carnitine. At day three of culture, each group was subdivided into two subgroups receiving no <span style="font-variant: small-caps;">l</span>-carnitine (group 1), 3.8 mM <span style="font-variant: small-caps;">l</span>-carnitine added during in vitro maturation (group 2), 1.5 mM added during the in vitro culture (group 3), and 3.8 mM and 1.5 mM added during the maturation and culture, respectively (group 4). At day 8, blastocyst embryos were examined for mitochondrial activity, the presence of lipid droplets, total cell number, gene expression, and cryotolerance by vitrification. The data were analyzed with a one-way analysis of variance. <span style="font-variant: small-caps;">l-</span>carnitine added in the late in vitro culture significantly reduced mitochondrial activity and lipid content, and upregulated <i>ifn-τ</i> and <i>ptgs2</i> gene expression compared to controls (<i>p</i> < 0.05). <span style="font-variant: small-caps;">l</span>-carnitine supplementation did not significantly affect the embryo rate production or survival rate after vitrification and warming (<i>p</i> > 0.05). <span style="font-variant: small-caps;">l</span>-carnitine supplementation significantly improved embryo potential to develop viable pregnancies in agreement with a study reporting improved pregnancy rates.