Transcriptome sequencing of Eospalax fontanierii to determine hypoxia regulation of cardiac fibrinogen.

With the increase in blood viscosity, the blood circulation resistance will increase when animals are in hypoxia. However, these phenomenons do not appear in hypoxic-adapted animals. Eospalax fontanierii is a subterranean rodent and is an ideal species for research in hypoxia adaptation. Eighteen healthy adult E. fontanierii individuals were equally divided into three groups that were exposed to 21% O2 for 1 week, 10.5% O2 for 44 h, and 6.5% O2 for 6 h, and then, the hearts were collected for transcriptome sequencing. After differentially expressed analysis, fibrinogen genes were selected for qPCR and Western blot verification. Eighteen healthy adult Sprague-Dawley rats (SD rats) were treated with the same oxygen concentrations, and their hearts were simultaneously subjected to qPCR. The quantitative real-time PCR and Western blot results were completely opposite to those of the rats. E. fontanierii fibrinogen mRNA was significantly downregulated when expressed under the conditions of 10.5% and 6.5% O2 compared with 21% O2. Correspondingly, fibrinogen mRNA in E. fontanierii was expressed at lower levels than SD rats in 10.5% and 6.5% O2. After tail-cutting experiment, the results showed that the coagulation rate of E. fontanierii was slowed down under hypoxic conditions. These results showed that E. fontanierii may downregulate the expression of fibrinogen mRNA in hypoxia to reduce the aggregation of red blood cells and platelets in plasma, which may prevent blood from becoming overly viscous, and at the same time, reduce blood circulation resistance and the probability of thrombosis in hypoxia to protect the heart.