Effects of Crocin Supplementation during In Vitro Maturation of Mouse Oocytes on Glutathione Synthesis and Cytoplasmic Maturation

Elham Mokhber Maleki; Hussein Eimani; Mohammad Reza Bigdeli; Afsane Golkar Narenji; Reyhane Abedi

doi:10.22074/ijfs.2016.4769

Effects of Crocin Supplementation during In Vitro Maturation of Mouse Oocytes on Glutathione Synthesis and Cytoplasmic Maturation

Int J Fertil Steril. 2016 Apr-Jun;10(1):53-61. doi: 10.22074/ijfs.2016.4769. Epub 2016 Apr 5.

Authors

Elham Mokhber Maleki¹, Hussein Eimani², Mohammad Reza Bigdeli³, Afsane Golkar Narenji³, Reyhane Abedi¹

Affiliations

¹ Department of Embryology, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran; Department of Embryology, Faculty of Biological Sciences, Shahid Beheshti University, Tehran, Iran.
² Department of Embryology, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran; Department of Anatomy, Faculty of Medicine, Baqiatallah (a.s.) University of Medical Sciences, Tehran, Iran.
³ Department of Embryology, Faculty of Biological Sciences, Shahid Beheshti University, Tehran, Iran.

Abstract

Background: Crocin is an active ingredient of saffron (Crocus sativus L.) and its antioxidant properties have been previously investigated. This carotenoid scavenges free radicals and stimulates glutathione (GSH) synthesis; consequently, it may protect cells against oxidative stress. The aim of this research is to protect oocytes from oxidative stress by the addition of a natural source antioxidant.

Materials and methods: In the present in vitro experimental study, we collected cumulus oocyte complexes (COCs) from mouse ovaries of euthanized, 6-8 week-old female Naval Medical Research Institute (NMRI) mice. Oocytes were subjected to in vitro maturation (IVM) in the presence of either crocin (5 or 10 μg/ml), 5 mM buthionine-[S-R]- sulfoximine (BSO), or the combination of crocin plus BSO. Oocytes that matured in vitro in a medium without crocin or BSO supplements were considered as controls. Following 16-18 hours of IVM, matured oocytes (n=631) were fertilized by capacitated sperm from NMRI male mice, and cultured in vitro for up to 96 hours to assess preimplantation embryonic development. The levels of GSH in metaphase II (MII) oocytes after IVM (n=240) were also assessed by the 5, 5-dithio-bis (2-nitrobenzoic acid) (DTNB)-GSH reductase recycling assay.

Results: Supplementation of IVM media with 10 µg/ml crocin significantly (P<0.05) increased nuclear maturation, preimplantation development and GSH concentrations compared with the control group. Maturation of oocytes in IVM medium supplemented with BSO alone or the combination of 5 µg/ml crocin and BSO drastically decreased GSH concentrations and subsequently resulted in low rates of maturation, fertilization and blastocyst development. However, the combination of 10 µg/ml crocin with 5 mM BSO increased the level of nuclear maturation which was comparable to the control group.

Conclusion: Supplementation of IVM media with crocin can improve nuclear maturation rates and subsequent developmental potential of mouse oocytes. This may occur by its beneficial effect in increasing GSH concentrations in MII oocytes.

Keywords: Crocin; Glutathione; In Vitro Maturation; Mouse; Oocyte.