en 39606683 <p style="text-align:justify"><span style="font-size:11pt"><strong><span style="font-size:10.0pt">Background:</span></strong><span style="font-size:10.0pt"> Simulated Physiological Oocyte Maturation (SPOM) mimics <em>in vitro</em> the physiological events of oocyte maturation in the presence of cAMP modulators. These modulators increase the intracellular concentrations of cAMP, which inhibits the immediate resumption of meiosis and gives the oocyte more time to gain optimal developmental competence. In addition, L-carnitine helps to increase the energy supply of cells through the &beta;-oxidation of fatty acids. This study aimed to investigate the effect of SPOM and L-carnitine supplementation during <em>In Vitro Maturation</em> (IVM) and In Vitro Culture (IVC) on the developmental competence of bovine oocytes.</span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><strong><span style="font-size:10.0pt">Methods:</span></strong><span style="font-size:10.0pt"> Ovarian Cumulus Complexes (COCs) were cultured in the presence or absence of forskolin+IBMX during the first 2 <em>hr</em> of IVM (pre-IVM) with or without L-carnitine (LC) during IVM or IVC in six experimental groups as follows: I) pre-IVM (pre-IVM group), II) pre-IVM with L-carnitine supplementation during IVM (pre-IVM/LC group), III) L-carnitine supplementation during IVM (IVM/LC group), IV) L-carnitine supplementation during <em>in vitro</em> culture (IVC/LC group), V) pre-IVM+ IVC/LC group, and VI) no treatment during IVM and IVC (Control group). The cleavage and blastocyst rates, the blastocysts&rsquo; total cells number, and the expression of <em>Nanog</em>, <em>Bax</em>, <em>Oct4</em>, <em>Cdx2</em>, and <em>Ifnt </em>genes in resulting blastocysts were assessed. To assess differences among experimental groups, a one-way analysis of variance was initially employed, followed by post hoc Fisher LSD. The difference between groups was considered statistically significant when p&lt;0.05.</span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><strong><span style="font-size:10.0pt">Results:</span></strong><span style="font-size:10.0pt"> The cleavage and blastocyst rates in the Pre-IVM and Pre-IVM/LC groups was higher than control group and other groups (p&le;0.05) except for IVC/LC and IVM/LC groups, respectively. The number of blastocyst&rsquo;s Inner Cell Mass (ICM) in pre-IVM and Pre-IVM/LC groups as well as the ratio of ICM/TE were higher than control group (p&lt;0.05). The expression of OCT4, CDX2, and IFNT increased in both the pre-IVM and pre-IVM/LC groups compared to the control group (p&lt;0.05).</span></span></p> <p style="text-align:justify"><span style="font-size:11pt"><strong><span style="font-size:10.0pt">Conclusion:</span></strong><span style="font-size:10.0pt"> In conclusion, the application of SPOM-adapted IVM and L-carnitine during IVM of bovine oocyte improves the quantity and quality of the resulting embryos. </span></span></p> 3-Isobutyl-l-methylxanthine, bcl-2-associated X protein, Blastocyst, Carnitine, Cattle, Meiosis, Oocytes, Pre-IVM 260 267 https://www.ajmb.org/En/Article.aspx?id=60593 https://www.ajmb.org/PDF/En/FullText/60593.pdf AliMalekpourSina Fanavaran Mandegar Company, Alborz Science and Technology Park, Kamalshahr, Iran92256AbolfazlShiraziSina Fanavaran Mandegar Company, Alborz Science and Technology Park, Kamalshahr, Iran82SaraBorjian BoroujeniSina Fanavaran Mandegar Company, Alborz Science and Technology Park, Kamalshahr, Iran337AliSarvariSina Fanavaran Mandegar Company, Alborz Science and Technology Park, Kamalshahr, Iran335Mohammad MehdiNaderiSina Fanavaran Mandegar Company, Alborz Science and Technology Park, Kamalshahr, Iran334MostafaPournourali Sina Fanavaran Mandegar Company, Alborz Science and Technology Park, Kamalshahr, Iran91924BaharehBehzadiDepartment of Embryology and Andrology, Avicenna Research Institute, ACECR, Tehran, Iran506Mohammad MehdiMehrazarDepartment of Embryology and Andrology, Avicenna Research Institute, ACECR, Tehran, Iran11473