Abstract
Oocytes of better quality and developmental competence are highly demanded, which is affected by many intrinsic and external factors, including environmental pollutants. We have previously demonstrated that 7, 12-dimethylbenz [a]anthracene (DMBA) reduces the developmental competence of porcine oocytes, by desynchronizing nuclear and ooplasmic maturation. However, the underlying molecular mechanism remains obscure. Here we performed single cell RNA-seq to study the transcriptome changes in DMBA-treated porcine MII oocytes, and identified 19 protein-coding genes and 156 novel long non-coding RNAs (lncRNAs) with abundance to be significantly different (P < 0.05), which enriched in signaling pathways such as glycosphingolipid biosynthesis, nicotine addiction, basal transcription factors and nucleotide excision repair. RT-qPCR on oocyte pools confirmed ornithine aminotransferase (Oat) and serine/arginine-rich splicing factor 4 (Srsf4) to be significantly up- and down-regulated, respectively (P < 0.05). Treating porcine COCs with MAPK and PLC pathway inhibitors suppressed DMBA's effects on increasing PB1 extrusion rate. In addition, DMBA co-incubation with 250 μM vitamin C derivative (l-ascorbic acid 2-phosphate sesquimagnesium salt hydrate, AA2P) and 100 μM co-enzyme Q10 (CoQ10) could significantly reduce the DMBA-induced high ROS level, and partially alleviate the DMBA-induced high PB1 rate, whereas the cleavage and blastocyst rates of parthenotes derived from treated mature oocytes remained to be low. Collectively, our findings indicate that single cell RNA-seq can help reveal the dynamics of molecular signaling pathways for porcine oocytes treated by DMBA, and supplement of anti-oxidative reagents could not sufficiently rescue DMBA-induced defects of porcine oocytes.