Effects of hypoxia on survival, apoptosis, and the transcriptome of the Chinese yellow pond turtle (Mauremys mutica)

Mauremys mutica is a widely cultured pond turtle in China that can hold its breath underwater for up to 7 h. However, the adaptive mechanism of this hypoxia-resistant phenotype remains unknown. In the present study, no M. mutica died until 6 h of hypoxic stress. Inflammation was observed in the lungs of dead individuals along with a lung cell apoptosis rate of 12.3% in the death group, which was about six times that of the survival group. Transcriptome sequencing produced 379,659,748 clean reads, and 38,981 genes were obtained. A total of 1566, 1555 and 756 differentially expressed genes (DEGs) were detected between the survival group and the death group, the survival group and the control group, and the death group and the control group, respectively. And the DEGs were enriched in the inflammation, apoptosis, sugar transport, antioxidant, fructose, and mannose metabolism, arginine and proline metabolism, glycosaminoglycan biosynthesis, P53, and MAPK signaling pathways. This study offers new insight into the molecular mechanisms occurring in the lungs of M. mutica during acute hypoxia, which may facilitate genetic selection for hypoxia-resistant lines in M. mutica.