In Vitro Embryo Production Efficiency in Cattle and Its Association with Oocyte Adenosine Triphosphate Content, Quantity of Mitochondrial DNA, and Mitochondrial DNA Haplogroup

Abstract

Mitochondria have a broad range of functions that affect reproduction, and structural as well as quantitative variation in mtDNA has been associated with gamete quality and reproductive success. To investigate the mitochondria effect on in vitro embryo production, we collected oocytes by ultrasound-guided follicular aspiration from donor cows known to differ in the developmental capacity, measured by the blastocyst formation rate, of their oocytes. To evaluate the potential effects of mtDNA and mitochondrial function on oocyte quality, the donor cows' mtDNA control region was sequenced and, after pairwise comparisons of polymorphisms, animals were grouped into two major haplogroups. The number of mtDNA molecules per oocyte was quantified by real-time PCR, and the adenosine triphosphate (ATP) content was measured in each oocyte to identify variations between haplogroups. Overall, ATP stocks in oocytes of the two haplogroups differed significantly (P < 0.05; means +/- SEM) both at the germinal vesicle and metaphase II stages (2.8 +/- 0.06 pmol vs. 2.6 +/- 0.07 pmol and 2.9 +/- 0.1 pmol vs. 2.3 +/- 0.06 pmol, respectively). The proportion of development to blastocyst was significantly different between haplogroups (22.3 +/- 2.1 % vs. 36.7 +/- 2.9 %). The number of mtDNA molecules per oocyte was highly variable (377 327 +/- 14 104, ranging from 2.0 x 10(3) to 1.2 x 10(6)) but not significantly different between the two haplogroups; significant differences were observed between animals without any apparent relationship to blastocyst production. These data suggest that mitochondria and mtDNA haplogroup affect the developmental capacity of bovine oocytes in vitro.

Astaxanthin ameliorates heat stress-induced impairment of blastocyst development In Vitro: –astaxanthin colocalization with and action on mitochondria–

“…Regarding mitochondria, oocytes in both species contain varied number of mitochondria, i.e., 20,000 to over 800,000 in human [48] and 2,000 to 1,200,000 in bovine [47] on mitochondrial DNA (mtDNA) basis. In human IVF, higher numbers of mtDNA are correlated with higher fertilizability or developmental competence of resulting eggs after fertilization [36,42].…”

Comparative Proteomic Analysis of Liver Mitochondrial Proteins Derived from Cloned Adult Pigs Reconstructed with Meishan Pig Fibroblast Cells and European Pig Enucleated Oocytes

“…In concert with mitochondrial dysfunction, abnormal nuclear reprogramming is a major factor in failure of iSCNT to conserve endangered species [31]. Previous reports provided evidence for oocyte mtDNA haplotype influences on SCNT efficiency in cattle [12,13,32]. Yan et al [14,33] demonstrated that donor-host mtDNA haplotype compatibility improved bovine SCNT efficiency; thus, homotypic SCNT blastocysts possess a more successful epigenetic symmetry pattern than heterotypic SCNT blastocysts.…”

“…Z3 was derived from SCNT embryos using in vitro matured oocyte and encapsulation methods with sodium alginate [24]. The oocyte environment during development could readily influence epigenetic changes in SCNT animals [32]. Interestingly, in a similar study in cattle, mitochondrial protein profiles varied among adult clones produced from the same cell line as used for the donor cells [26].…”

Mitochondries et reproduction

“…Le taux d'hétéroplasmie de ces délétions étant voisin de 0,1%, il semble peu probable qu'il puisse entraîner un quelconque retentissement fonctionnel [23]. Enfin, de récents résultats obtenus sur des ovocytes de vache démon-trent que les haplogroupes mitochondriaux influencent le taux de production de blastocystes indépendamment de la qualité du sperme utilisé [24]. Cette donnée suggère un effet maternel important porté par l'ADNmt.…”