March 2015 (No. 1) Volume 15
Intracytoplasmic sperm injection affects embryo developmental potential and gene expression in cattle
María Elena Arias a, Jennie Risopatrón a, Raúl Sánchez a, Ricardo Felmer a,b,*
a Laboratory of Reproduction, Centre of Reproductive Biotechnology (CEBIOR-BIOREN), Faculty of Medicine, Universidad de La Frontera, Temuco, Chile
b Department of Agricultural Sciences and Natural Resources, Faculty of Agriculture and Forestry, Universidad de La Frontera, Temuco, Chile
Some reports have linked intracytoplasmic sperm injection (ICSI) with chromosomal abnor- malities, low developmental potential and altered gene expression in embryos. ICSI has also been linked with obesity, early aging and increased incidence of tumors in offspring. Other reports have demonstrated that some of these complications disappeared within a few weeks of life or even showed a lack of such associations. The aim of this study was to evaluate and compare embryo development, quality and gene expression in bovine embryos generated by ICSI and by conventional in vitro fertilization (IVF) insemination. The results showed differ- ences in cleavage (88.5% in IVF and 64.1% in ICSI) and blastocyst formation rates (36.1% in IVF and 22.3% in ICSI). The proportion of ICM cells to total cell count was higher in ICSI (39.2%) than in IVF embryos (29.5%). However, no differences were observed in the total embryonic cell numbers (159.3 ± 28.5 and 161.2 ± 56.2 for IVF and ICSI, respectively) or in the proportion of apoptotic nuclei to the total embryonic cell numbers (2.12 and 2.64% for IVF and ICSI, respectively). Gene expression analysis showed a down-regulation of insulin-like growth factor 2 (IGF2) and overexpression of bcl-2-like protein 4 (BAX), octamer-binding transcription factor four (OCT4), interferon-tau (IFNt), Mn-superoxide dismutase in the mitochondria (SOD2), and catalase (CAT) in embryos generated by ICSI. In conclusion, our study demonstrated differences in the morphological development of bovine embryos as well as in the expression of genes involved in early development between ICSI and IVF embryos. The results may indicate lower developmental potential of ICSI embryos compared with that of IVF.
Reproductive Biology 2015, 15, 1: 34-41.
* Corresponding author at: Laboratory of Reproduction, Centre of Reproductive Biotechnology (CEBIOR-BIOREN), Faculty of Agriculture and Forestry, Universidad de La Frontera, Montevideo 0870, P.O. Box 54-D, Temuco, Chile; e-mail address: firstname.lastname@example.org (R. Felmer)