MiR-133b regulates the expression of the actin protein TAGLN2 during oocyte growth and maturation: a potential target for infertility therapy

In this study, the expression of miRNAs in metaphase I (MI) oocytes treated with or without insulin-like growth factor 1 (IGF-1) was observed by microRNA microarray analysis. Results show that 145 miRNAs were up-regulated and 200 miRNAs were down-regulated in MI oocytes after IGF-1 treatment. MiR-133b, which was up-regulated more than 30-fold, was chosen for further research. The isolated MI oocytes were cultured at 37°C and 5% CO2 in G-2TM PLUS (Vitrolife, Sweden) treated with (45 oocytes) or without (62 oocytes) 200 ng/ml IGF-1 for 24 h (Peprotech, USA), then covered with ovoil (Vitrolife, Sweden). After 24 h, all oocytes were stored at 80°C until RNA was extracted. The average age of patients without IGF-1 treatment was 31.66 ± 3.90. The average age of patients with IGF-1 treatment was 31.25 ± 3.31. No apparent bias was detected between these two groups.