The cytokine platelet factor 4 successfully replaces bovine serum albumin for the in vitro culture of porcine embryos

The cytokine platelet factor 4 (PF4) enhances differentiation and cell viability of different stem cells lines in vitro. This study investigated whether PF4 addition to customary pig embryo semi-defined culture media can improve their developmental outcome (Experiment 1) and ultimately replace the need for bovine serum albumin (BSA, Experiment 2). Experiment 1 added PF4 (100-1000 ng/mL, 0 = control) to NCSU-23 with 0.4 mg/mL BSA culturing 3430 presumptive zygotes. Experiment 2 added PF4 (100 -1000 ng/mL, 0 = Control-PVA) to a BSA-free medium (NCSU-23 with 0.3 mg/mL PVA) culturing 3820 presumptive zygotes. Zygote culture in NCSU-23 with 0.4 mg/mL BSA was used as overall control. All groups of Experiment 1 displayed similar rates of day 2-cleavage (range: 65.0 +/- 10.9 to 70.0 +/- 5.8%); of day 7-blastocyst rates (range: 46.6 +/- 10.0 to 56.4 +/- 8.2%) and of total day 7-blastocyst efficiency (range: 32.3 +/- 8.3 to 37.2 +/- 7.3%). Addition of PF4 did not affect total cell numbers of day 7 blastocysts (range: 44.1 +/- 23.2 to 50.5 +/- 26.4). In Experiment 2, PF4 accelerated embryo development, increasing (P < 0.01) blastocyst yield compared to 0-PF4, and blastocyst formation by day 5 adding PF4 100-500 ng/mL (range: 29.9 +/- 7.8 to 31.8 +/- 5.5%; P < 0.05) compared with BSA-control (17.2 +/- 8.2%) and PF4 1000 ng/mL (15.5 +/- 7.9%); showing similar blastocyst rates (range: 42.0 +/- 11.5 to 49.3 +/- 10.0%), total efficiency (28.0 +/- 8.2 to 32.3 +/- 7.1%) total cell numbers (range: 42.6 +/- 19.3 to 45.7 +/- 23.9) as BSA-controls. In conclusion, although PF4 did not show additive improvement under usual semi-defined, BSA-supplemented embryo media, it successfully replaced BSA sustaining porcine blastocyst production in chemically defined conditions. (C) 2019 Elsevier Inc. All rights reserved.