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Figure 4 | Reproductive Biology and Endocrinology

Figure 4

From: Effect of holding equine oocytes in meiosis inhibitor-free medium before in vitro maturation and of holding temperature on meiotic suppression and mitochondrial energy/redox potential

Figure 4

Photomicrographs of equine oocytes fixed after recovery (IMM) or held overnight in EH medium at 25°C (EH), assessed for nuclear chromatin and energy/redox potential. Bright field, epifluorescence and confocal images indicating morphology (A1-F1), chromatin configuration (A2-F2), mitochondrial (mt) distribution pattern (A3-F3), intracellular ROS localization (A4-F4), mt/ROS merged (A5-F5) and the mt/ROS colocalization scatter plot graph (A6-F6; Y axis: mt fluorescence intensity; X axis: ROS fluorescence intensity). A, EH-treated oocyte showing FN chromatin (A2), homogeneous distribution of small mt aggregates (SA; A3), ubiquitous ROS localization (A4), poor mt/ROS colocalization (A5), and low fluorescence intensity with wide red/green scatter, supporting lack of colocalization of ROS and mt signals (A6); B, EH-treated oocyte showing intermediate chromatin (B2), SA mt distribution (B3), but with higher mt intensity and greater mt/ROS colocalization compared to A (longer and narrower scatter plot); C, EH-treated oocyte showing condensed chromatin (C2; the nuclear outline in the mt image confirms this as a GV configuration), heterogenous perinuclear and pericortical mt pattern (P/P, C3), localized ROS distribution in areas with and without mt labeling (C4, C5), and the mt/ROS scatter plot (C6) showing greater fluorescence intensity than in A and B, with predominance of mt fluorescence (Y axis); D, IMM oocyte showing intermediate chromatin (D2), P/P mt pattern (D3), ROS localization in areas with and without mt labeling (D4, D5), and less precise mt/ROS colocalization, as shown by the broader scatter plot (D6); E, IMM oocyte showing condensed chromatin with nuclear outline and heterogeneous mt/ROS distribution, similar to D; F, IMM-MII oocyte, likely from an atretic follicle, showing MII chromatin at 7:00 (F2; cumulus cell nucleus at 12:00); P/P mt pattern (F3), ROS localization in areas with and without mt labeling (F4, F5), and a broad scatter plot, suggesting poor mt/ROS colocalization (F6). The scale bar represents 60 μm.

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Reproductive Biology and Endocrinology

ISSN: 1477-7827

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