α-solanine is toxic to human health by disturbing digestive and central nervous systems. However, little information has been focused on investigated with respect to α-solanine influence in mammal oocyte maturation and quality. In this study, we investigated the effects of α-solanine on oocyte maturation, quality and possible molecular mechanisms in a pig model. Porcine Cumulus-oocyte complexes (COCs) were treated with increasing concentration (0, 1, 10, 20, 50 μM) of α-solanine subjected to further in vitro maturation culture. The result showed that α-solanine significantly inhibited cumulus cells expansion and increased oocyte death rates when the concentration of α-solanine more than 10 μM. After cell cycle and cytoskeleton analysis, the results showed that α-solanine (10 μM) disturbed meiotic resumption, increased abnormal spindle formation and cortical granules (CGs) distribution rates when compared with the untreated group. α-solanine (10 μM) triggered autophagy by increasing the expression of autophagy-related genes (LC3, ATG7, LAMP2) and accumulation of LC3-specific puncta (an autophagy maker). TUNEL staining assay showed that α-solanine significantly increased apoptosis in porcine oocytes confirmed by up-regulated the levels of BAX and CAPS3 genes. Further study revealed that exposure α-solanine (10 μM) to porcine oocytes induced ROS generation, reduced mitochondrial membrane potential. In addition, our results suggested that α-solanine (10 μM) significantly increased the levels of H3K36me3 and H3K27me3 in porcine oocytes. Taken together, these data indicated that α-solanine toxic impaired oocyte maturation and quality by inhibited cumulus cells expansion, increased abnormal spindle and CGs distribution rates, triggered autophagy/apoptosis occur, accumulated ROS, decreased mitochondrial membrane potential, and changed epigenetic modifications.

In pig, more than half of the recovered cumulus cell-oocyte complexes (COCs) have one or two layers of cumulus cells and are considered morphologically poor. If we could take full advantage of these poor quality COCs, we could potentially improve the efficiency of in vitro embryo production. During in vitro maturation, although some maturation factors are transmitted bidirectionally between the oocyte and cumulus cells of the same COC, transmission also occurs between different COCs. We hypothesized that morphologically poor COCs fail to undergo complete oocyte maturation due to their insufficient secretion of maturation factors. Here, we investigated whether co-culture with morphologically good COCs (having three or more layers of cumulus cells) could improve the maturation and utilization rates of morphologically poor COCs. Our results revealed that the oocyte maturation rate, glutathione level, embryo development capacity, blastocyst quality, and cumulus cell gene expression levels of BCL-2 and PCNA were similar in the co-culture and good quality-groups, and that these levels were all significantly higher than those in the poor quality-group. Our results strongly suggest that the co-culture strategy greatly improved the utilization rate of morphologically poor COCs without reducing their capacity for maturation and subsequent development.

Early pregnancy results in th production of various signal molecules such as steroids, prostaglandins, and many protein factors. The proteins especially produced by the placenta have been used to detect pregnancy for many years in other species. More recently, pregnancy-specific protein B, which is a placental glycoprotein can be measured by RIA or proteomic methods in serum of pregnant cow. And 2D Fluorescence difference gel electrophoresis (DIGE) is an emerging technique for comparative proteomics, which improves the reproducibility and reliability of differential protein expression analysis between samples. For this reason, we are analyzed serum of bovine. The purpose of this study was to apply DIGE technique for identification of bovine pregnancy-specific proteins using bovine pregnant and non-pregnant serum samples. Serums of 2 pregnant Holstein dairy cattle at day 21 after AI and those of 2 non-pregnant were used in this study. The molecular weight and charge matched cyanine dyes enable pre-electrophoretic labeling of non-pregnancy and pregnant serum proteins which are then mixed and labeled with Cy2 were used as an internal standard. Two pools of proteins are labeled with Cy3 and Cy5 fluorescent dyes, respectively. Labeled proteins with Cy2, Cy3 and Cy5 mixed together and separated in same gel and then were detected by fluorescence image analyzer. The 2D DIGE analysis using fluorescence CyDye flour showed higher sensitivity and better reproducible results than conventional 2D gel electrophoresis. Approximately 1,500 protein spots were detected by 2D DIGE. The differentially expressed proteins were identified by MALDI-TOF Mass spectrometer. Total 16 protein spots differentially expressed in the pregnant serum were detected, among which 7 spots were up-regulated proteins identified as conglutinin precursor, modified bovine fibrinogen, IgG1 etc, and 6 spots were down-regulated proteins identified as hemoglobin, complement component 3, bovine fibrinogen, IgG2a etc. These results indicated that DIGE system could be advantageous for the analysis of serum proteomics diversified by physiological conditions.