The effect of kinetic heat shock on bovine oocyte maturation and subsequent gene expression of targeted genes

• Published in: Zygote (Cambridge) Vol. 25; no. 3; pp. 383 - 389
• Main Authors: Pavani, Krishna C., Rocha, António, Baron, Erica, Lourenço, Joana, Faheem, Marwa, da Silva, Fernando Moreira
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 01.06.2017
• Subjects: Animals; Apoptosis; Assaying; Cadherins - genetics; Cattle; Cell cycle; Connexin 43; Connexin 43 - genetics; Deoxyribonucleic acid; DNA; DNA (Cytosine-5-)-Methyltransferase 1 - genetics; DNA methylation; DNMT1 protein; E-cadherin; Embryos; Experiments; Female; Fertilization; Gene expression; Gene Expression Regulation; Gene regulation; Genes; Glyceraldehyde-3-phosphate dehydrogenase; Heat; Heat shock; Heat stress; Heat tolerance; Heat-Shock Response; HSP70 Heat-Shock Proteins - genetics; In Vitro Oocyte Maturation Techniques - methods; Maturation; Oocytes; Oocytes - physiology; Organelles; Proteins; Ribonucleic acid; RNA; Seasons; Short Communication; Stressing; Summer; Temperature effects; Winter; Kinetic heat shock; Gene quantification; Maternal heat stress; Apoptosis
• ISSN: 0967-1994; 1469-8730
• DOI: 10.1017/S0967199417000223

The exposure of oocytes to heat stress during the maturation process results in harmful effects to their internal organelles, low fertilization capability and higher embryonic losses. In the present experiment the effect of heat shock (HS) during the maturation process was assessed. In Assay 1, oocytes from winter (December–March; n = 100) and summer (June–September; n = 100) months were collected and matured to analyse their HS tolerance. Total RNA was extracted from matured oocytes and cDNA synthesis was performed, followed by qPCR for selected genes (Cx43, CDH1, DNMT1, HSPA14), compared with two reference genes (GAPDH and SDHA). In Assay 2, oocytes collected during the winter were subjected to kinetic HS by stressing them at 39.5°C for 6, 12, 18 or 24 h and were afterwards matured at control temperature (38.5°C), and subsequently subjected to the previously described gene analysis procedure. Results of Assay 1 show that summer-collected oocytes exhibited lower maturation rate than winter-collected oocytes, which may be due to the down-regulation of the HSPA 14 gene. Assay 2 showed that 6 h of HS had no effect on gene regulation. CDH1 and DNMT1 up-regulation was observed starting at 12 h, which may represent the effect of heat shock on oocyte development.