Fig. 4

hAMSC transplantation improved oocyte quality and subsequent embryo development. a Morphology of 2-cell embryos. On the second day after fertilization, the zygote in the zona pellucida mitoses into 2 cells; no obvious difference was observed between groups under the microscope. Scale bar: 200 μm. b Morphology of blastocysts. On the fifth day after fertilization, the zygote mitosis develops into a blastocyst which forms a cyst cavity and/or breaking through the zona pellucida; no obvious difference was observed between groups under a microscope. Scale bar: 200 μm. c The rates of 2-cell formation (2-cell embryos/retrieval oocytes) were evaluated in groups and they were increased in the LD, MD, and HD groups. n = 8. d Rates of blastocyst formation (blastocyst embryos/2-cell embryos) were evaluated in groups and they were significantly increased in the LD, MD, and HD groups. n = 8. e The rates of gestation (pregnant mice with live fetus/total mice) were evaluated in groups and they were increased in the LD, MD, and HD groups. f Numbers of average live fetus were evaluated in groups. The HD group had a significantly higher number of live fetus. The number of mice analyzed in e and f was 7, 8, 8, 7, and 6, respectively for NS, HSA, LD, MD, and HD groups. Assays on 2-cell formation (a, c) and blastocyst formation (b, d) were performed at day 7 post-transplantation of hAMSCs. Assays on gestation (e) and live fetus (f) were performed at about day 15 post-transplantation of hAMSCs. NS: normal saline group; HSA: 1% human serum albumin group; LD: low-dose group; MD: middle-dose group; HD: high-dose group. Error bars indicate SEM. Different lowercase letters represent significantly statistical differences (P < 0.05)