title: The potential role of granulosa cells in the maturation rate of immature human oocytes and embryo development: A co-culture study.
abstract: OBJECTIVE
  In order to increase the number of mature oocytes usable for intracytoplasmic sperm injection (ICSI), we aimed to investigate the effect of co-culturing granulosa cells (GCs) on human oocyte maturation in vitro, the fertilization rate, and embryo development.
  
  
  METHODS
  A total of 133 immature oocytes were retrieved and were randomly divided into two groups; oocytes that were cultured with GCs (group A) and oocytes that were cultured without GCs (group B). After in vitro maturation, only oocytes that displayed metaphase II (MII) underwent the ICSI procedure. The maturation and fertilization rates were analyzed, as well as the frequency of embryo development.
  
  
  RESULTS
  The mean age of the patients, their basal levels of follicle-stimulating hormone, and the number of oocytes recovered from the patients were all comparable between the two study groups. The number of oocytes that reached MII (mature oocytes) was 59 out of 70 (84.28%) in group A, compared to 41 out of 63 (65.07%) in group B (p=0.011). No significant difference between fertilization rates was found between the two study groups (p=0.702). The embryo development rate was higher in group A (33/59, 75%) than in group B (12/41, 42.85%; p=0.006). The proportion of highest-quality embryos and the blastocyst formation rate were significantly lower in group B than in group A (p=0.003 and p<0.001, respectively).
  
  
  CONCLUSIONS
  The findings of the current study demonstrate that culturing immature human oocytes with GCs prior to ICSI improves the maturation rate and the likelihood of embryo development.
authors.affiliation: Infertility Research Center, Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Bahia Namavar
authors.initials: BN
authors.lastname: Jahromi
authors.affiliation: Student Research Committee, Department of Obstetrics and Gynecology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Mosallanezhad
authors.affiliation: Infertility Research Center, Mother and Child Hospital, Shiraz, Iran.
authors.forename: Najmeh
authors.initials: N
authors.lastname: Matloob
authors.affiliation: Infertility Research Center, Mother and Child Hospital, Shiraz, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Davari
authors.affiliation: Zoonoses Research Center, Faculty of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran.
authors.forename: Mohamed Amin
authors.initials: MA
authors.lastname: Ghobadifar
keywords: Fertilization; Granulosa cells; In vitro oocyte maturation techniques; Intracytoplasmic sperm injection; Oocytes