Osteopontin (OPN) and Leukemia Inhibitory Factor (LIF) and Your Receptor (LIF-R) Genes in the Canine Embryos
The objective of this study was to assess the gene expression of hormone receptors for OPN, LIF and LIF-R in canine embryos.
Ten healthy bitches were inseminated and the ovariohysterectomy was performed 8 days after the LH surge (n = 5) and 12 d after the LH (n = 5), for collected morulas and blastocysts respectively. The oviduct and uterus were flushed and five embryos/female were frozen and stored in RNA later at -80°C. The RNA extraction was performed using the Quiagen RNeasy micro-kit and the DNase I Amplification Grade. For the reverse transcription, we used the kit SuperScript II and SuperScript III. RT-qPCR was performed with the power SYBR Green PCR Master Mix. The constitutive gene used was HPRT. The relative gene expression was determined by student t-test.
The LIF-R was expressed only in canine blastocysts (4.20 ± 0.02). There was no detection of mRNA LIF and OPN in morulae and blastocysts. The absence the OPN mRNA expression in canine morulae and blastocysts are similar to results found in pigs and rabbits and the absence of LIF mRNA expression in all embryos is a different result from those obtained by Schafer-Somi et al. (2008).
That difference in results may be associated with low quantity of RNA extracted from embryonic structures in our study. Hou and Grouski (1993) reported that specific genes are expressed in the transition of morula to blastocyst, and there are changes in the synthesis and secretion of specific proteins from the early late blastocyst.