Carbohydrate and Lipid Metabolism Characteristics of Hypoxia Tolerance in Gastrocnemius of the Gansu zokor, Eospalax cansus

Abstract

Gansu zokor (Eospalax cansus) is a typical subterranean rodent species, and the balance between energy production and consumption has critical function for this creature to adapt to its hypoxia environment. However, little is known about the energy metabolism of gastrocnemius in Gansu zokor. Thus, we exposed Gansu zokors and similar-sized Sprague-Dawley rats (SD rats) to normoxia (21% O2), hypoxia I (6h at 6.5% O2), hypoxia II (44h at 10.5% O2) or hypoxia III ( 10d at 10.5% O2). We fi rst compared the plasma glucose and plasma lipid levels in Gansu zokor with those in SD rats; and we found that Gansu zokor had a higher overall plasma lipid levels than those in SD rats, interestingly, compared with SD rats, the plasma glucose level in Gansu zokor was no higher in all groups and even signifi cantly lower in the normoxia and hypoxia III. Furthermore, transcriptomic analysis of gastrocnemius in Gansu zokor (6.5% O2 VS 21% O2) indicated its carbohydrate and lipid metabolic alterations after exposed to hypoxia, suggesting that the change in metabolism was linked to the hypoxia environment. Hence, we then measured the transcriptional and translational levels of carbohydrate and lipid metabolism-related genes, glucose and fructose levels in gastrocnemius. We found that unlike rat, Gansu zokor gastrocnemius enhanced fructose-driven metabolism through increased the fructose transporter (GLUT5) expression in all hypoxia groups, and Gansu zokor also could enhanced lipid metabolism by increasing the expression of acetyl-Coenzyme A acyltransferase 2 (ACAA2) and stearoyl-CoA desaturase 1 (SCD1) after exposure to long-term hypoxia condition (10d at 10.5% O2). Overall, these fi ndings indicate that Gansu zokor could increase energy supply by enhancing fructose-driven metabolism and lipid metabolism to cope with hypoxia environment, which playing an important role in hypoxia tolerance.