Vitrification of bovine blastocysts pretreated with sublethal hydrostatic pressure stress: evaluation of post-thaw in vitro development and gene expression

• Published in: Reproduction fertility and development Vol. 23; no. 4; pp. 585 - 590
• Main Authors: Siqueira Filho, E, Caixeta, E.S, Pribenszky, C, Molnar, M, Horvath, A, Harnos, A, Franco, M.M, Rumpf, R
• Format: Journal Article
• Language: English
• Published: Australia CSIRO Publishing 01.01.2011
• Subjects: Animals; Blastocyst - metabolism; Blastocyst - physiology; cattle; Cattle - embryology; Cell Survival; Cells, Cultured; cryopreservation; Cryopreservation - methods; Embryo Culture Techniques; Embryonic Development - physiology; Female; Fertilization in Vitro; Gene Expression; genes; germ cells; hatching; Hydrostatic Pressure; in vitro culture; Male; pressure treatment; Stress, Mechanical; Vitrification
• ISSN: 1031-3613
• DOI: 10.1071/RD10203

Sublethal stress treatment has been reported to enhance gametes' performance in subsequent procedures, such as cryopreservation. The aim of the present study was to evaluate the effect of different equilibration times between the termination of a sublethal hydrostatic pressure (HP) stress treatment and the initiation of vitrification on the post-thaw survival, continued in vitro development, hatching rate and gene expression of selected candidate genes of in vitro-produced (IVP) expanded bovine blastocysts. Day 7 IVP blastocysts were subjected to 600 bar pressure for 60min at 32°C. Immediately after pressure treatment (HP0h) or after 1 or 2h incubation (HP1h and HP2h groups, respectively), embryos were either vitrified and warmed using the open pulled straw method, followed by 72h in vitro culture or were stored at -80°C until gene expression analysis. Re-expansion and hatching rates after vitrification-warming were significantly (P<0.05) higher in the HP0h (88 and 76%, respectively) and HP1h (90 and 75%, respectively) groups than in the untreated (82 and 63%, respectively) and HP2h groups (79 and 70%, respectively). Moreover, the HP1h group showed further improvement in the speed of re-expansion and resumption of normal in vitro development. Cumulative analysis of all genes (SC4MOL, HSP1A1A, SOD2 and GPX4) revealed a similar pattern of expression, with a tendency for peak transcript abundance 1h after HP treatment. Application of HP stress treatment was found to be efficient in increasing the in vitro developmental competence of vitrified bovine embryos.