Exposure of Preimplantation Embryos to Insulin Alters Expression of Imprinted Genes

Author： Shao Wei-Juan Tao Ling-Yun Xie Jian-Yun Gao Cheng Hu Jian-Hua Zhao Ru-Qian

Publisher： American Association for Laboratory Animal Science

ISSN： 1532-0820

Source： Comparative Medicine, Vol.57, Iss.5, 2007-10, pp. : 482-486

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

Insulin promotes early embryonic development, but whether this action affects postimplantation fetal development and alters the expression of imprinted genes remain to be determined. This study analyzed the expression and methylation levels of the growthrelated imprinted genes H19 and insulin-like growth factor 2 (Igf2) in fetuses exposed to insulin before implantation. We cultured 2-cell embryos in either 0 or 0.25 μg/ml insulin until the blastocyst stage and then transferred them into pseudopregnant recipient mice. The number of embryos developing to blastocysts after insulin exposure was 16.4% higher than that of the control, and the birth body weight of the insulin-exposed group was 17.8% higher than that of the control group. Real-time reverse transcription– polymerase chain reaction analysis revealed that exposure of preimplantation embryos to insulin increased the mRNA expression of both Igf2 and H19 in embryonic day (E) 14 fetuses. Bisulfite genomic sequencing demonstrated that the methylation level of the H19–Igf2 imprint control region was 19.3% lower in insulin-exposed E14 fetuses than in controls. The present study indicates that insulin exposure during the preimplantation stage alters the expression of imprinted genes and affects fetal development.