Research Paper Volume 13, Issue 14 pp 18018—18032

GAS6 ameliorates advanced age-associated meiotic defects in mouse oocytes by modulating mitochondrial function

GAS6 ameliorates age-associated meiotic defects in oocytes. (A) Micrographs of aged MII oocytes treated without or with the GAS6 protein. Control, nontreated MII oocyte; GAS6-rescued, MII oocyte treated with the GAS6 protein. The scale bar represents 100 μm. (B) In vitro maturation rates of aged mouse oocytes after the microinjection of the GAS6 protein into GV-stage oocytes. After GAS6 restoration, these oocytes developed into morphologically normal MII oocytes, similar to the control groups. The data are presented as the means ± SEM. (C, D) Microinjection of the GAS6 protein led to a partial recovery of the decreased GAS6 levels induced by maternal aging. α-TUBULIN was used as a loading control. Relative expression levels of the GAS6 protein are presented in a bar graph and compared to the control young oocyte group. The data are presented as the means ± SEM. Different letters indicate significant differences at pE) Immunofluorescence staining for spindles and chromosomes in aged MII oocytes after injection of the GV oocytes without (control) or with the GAS6 protein (GAS6-rescued), which were then allowed to mature in vitro. Green, spindle; blue, chromosome; red, mitochondria; red box, oocyte with abnormal spindle and chromosome alignment. The scale bars represent 25 μm. (F) Proportions of control or GAS6 protein-injected MII oocytes with defects in spindle assembly and chromosome configuration.

Figure 2. GAS6 ameliorates age-associated meiotic defects in oocytes. (A) Micrographs of aged MII oocytes treated without or with the GAS6 protein. Control, nontreated MII oocyte; GAS6-rescued, MII oocyte treated with the GAS6 protein. The scale bar represents 100 μm. (B) In vitro maturation rates of aged mouse oocytes after the microinjection of the GAS6 protein into GV-stage oocytes. After GAS6 restoration, these oocytes developed into morphologically normal MII oocytes, similar to the control groups. The data are presented as the means ± SEM. (C, D) Microinjection of the GAS6 protein led to a partial recovery of the decreased GAS6 levels induced by maternal aging. α-TUBULIN was used as a loading control. Relative expression levels of the GAS6 protein are presented in a bar graph and compared to the control young oocyte group. The data are presented as the means ± SEM. Different letters indicate significant differences at p<0.05. Control, nontreated oocyte; GAS6-rescued, oocyte treated with the GAS6 protein; Young, oocytes obtained from 3-week-old female mice; Aged, oocytes obtained from 12-month-old female mice. (E) Immunofluorescence staining for spindles and chromosomes in aged MII oocytes after injection of the GV oocytes without (control) or with the GAS6 protein (GAS6-rescued), which were then allowed to mature in vitro. Green, spindle; blue, chromosome; red, mitochondria; red box, oocyte with abnormal spindle and chromosome alignment. The scale bars represent 25 μm. (F) Proportions of control or GAS6 protein-injected MII oocytes with defects in spindle assembly and chromosome configuration.