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Development of Pre-implantation Porcine Blastocysts cultured within Alginate Hydrogel Systems either supplemented with Secreted Phosphoprotein 1 or conjugated with Arg-Gly-Asp Peptide
Although deficiencies in porcine blastocyst elongation play a significant role in early embryonic mortality and establishment of within–litter developmental variation, the exact mechanisms of elongation are poorly understood. Secreted phosphoprotein 1 (SPP1) is increased within the uterine milieu during early porcine pregnancy and contains an Arg-Gly-Asp (RGD) peptide sequence that binds to cell surface integrins on the uterine endometrium and trophectoderm promoting cell adhesion and migration. The objective of the current study was to evaluate development of pre-implantation porcine blastocysts encapsulated and cultured within alginate hydrogels either supplemented with SPP1 or conjugated with RGD. This study demonstrated that blastocysts encapsulated within alginate hydrogels supplemented with SPP1 or conjugated with RGD had increased survival compared to non-encapsulated control blastocysts. In addition, blastocysts encapsulated within RGD-hydrogels had improved percentage of morphological changes compared to blastocysts within standard alginate hydrogels or SPP1-supplemented hydrogels. Finally, only blastocysts encapsulated within RGD-hydrogels had both increased expression of steroidogenic and immune responsiveness transcripts and increased 17β-estradiol production, consistent with blastocysts undergoing elongation in vivo. These results illustrate the importance of the integrin binding RGD peptide sequence for stimulating the initiation of blastocyst elongation.
RD16366 Accepted 14 March 2017
© CSIRO 2017