Role of activated dynamin-related protein 1-mediated glutathione metabolism in regulation of mitochondrial dysfunction after hemorrhagic shock

Abstract

Objective To explore the relationship between activated dynamin-related protein 1 (Drp1)-mediated mitochondrial function and energy metabolism after hemorrhagic shock and clarify its potential mechanisms. Methods Sixty C57 female mice (8-weeks old, weighing about 20 g) were randomly divided into shock+WT group (n=30, treated with hemorrhagic shock) and Normal+WT group (n=30). Thirty Drp1 KO C57 female mice (8-weeks old, weighing about 20 g) were treated with hemorrhagic shock as shock+Drp1 KO group, and the other 30 KO mice were regarded as Normal+Drp1 KO group. The changes of energy metabolism, mitochondrial metabolism, mitochondrial functions as well as Drp1 activity in vascular tissues after hemorrhagic shock were observed in WT and KO mice respectively. Vascular smooth muscle cells (VSMCs) were treated with Drp1 over-expression and exogenous glutathione (10 mmol/L) to confirm the effects of Drp1 and glutathione on mitochondrial functions after shock. Results After hemorrhagic shock, the energy metabolism and mitochondrial metabolism, such as glutathione, were decreased significantly (P < 0.05), mitochondrial reactive oxygen species (ROS) production were increased by 2.3 times (P < 0.05), ATP content was decreased by 67.8% (P < 0.05), and mitochondrial respiratory rates were decreased by 50% (P < 0.05). However, hypoxia resulted in the ROS production of VSMCs enhanced by 4 times and the mitochondrial membrane potential (ΔΨm) decreased by 76.7% (P < 0.05). What's more, both Drp1 activation and mitochondrial translocation were observed in shock-treated mice and hypoxia-induced VSMCs. The level of glutathione was 1.35±0.0.42 nmol/μg in normal+WT group, 0.55±0.20 nmol/μg in shock+WT group, while the level in shock+Drp1 KO group (0.94±0.30 nmol/μg) was much higher than that in shock+WT group (P < 0.05). Drp1 over-expression induced ROS level in VSMCs increased by 3.3 times and ΔΨm decreased by 70% (P < 0.05). After further exogenous glutathione supplementation, both ROS level and ΔΨm were improved significantly (P < 0.05). Conclusion Activated Drp1 after hemorrhagic shock induces mitochondrial dysfunctions and abnormal energy metabolism by inhibiting glutathione metabolism.

Keywords

• shock
• hypoxia
• mitochondria
• dynamin-related protein 1
• glutathione
• energy metabolism