Mitochondrial dysfunction in rat splenocytes following hemorrhagic shock

Abstract

The regulation of mitochondrial function is critical in cellular homeostasis following hemorrhagic shock. Hemorrhagic shock leads to fluid loss and reduced availability of oxygen and nutrients to tissues. The spleen is a secondary lymphoid organ playing a key role in ‘filtering the blood’ and in the innate and adaptive immune responses. To understand the molecular basis of hemorrhagic shock, we investigated the changes in splenocyte mitochondrial respiration, and concomitant immune and metabolic alterations. The hemorrhagic injury (HI) in our rat model was induced by bleeding 60% of the total blood volume followed by resuscitation with Ringers lactate. Another group of animals was subjected to hemorrhage, but did not receive fluid resuscitation. Oxygen consumption rate of splenocytes were determined using a Seahorse analyzer. We found a significantly reduced oxygen consumption rate in splenocytes following HI compared to sham operated rats. The mitochondrial stress test revealed a decreased basal oxygen consumption rate, ATP production, maximal respiration and spare respiratory capacity. The mitochondrial membrane potential, and citrate synthase activity, were also reduced in the splenocytes following HI. Hypoxic response in the splenocyte was confirmed by increased gene expression of Hif1α. Elevated level of mitochondrial stress protein, hsp60 and induction of high mobility group box1 protein (HMGB1) were observed in splenocytes following HI. An increased inflammatory response was demonstrated by significantly increased expression of IL-6, IFN-β, Mip-1α, IL-10 and NFκbp65. In summary, we conclude that splenocyte oxidative phosphorylation and metabolism were severely compromised following HI.

Therapeutic interventions to restore microcirculatory perfusion following experimental hemorrhagic shock and fluid resuscitation: A systematic review

“…7,10 Tissue edema increases diffusion distances between capillaries 11 leading to impaired tissue perfusion, reduced ATP production, and mitochondrial dysfunction. 12,13 Blood transfusion, hypothermia, and acidosis are other factors evoking the development of coagulopathy, complement activation, 14 and systemic inflammation. 7,15 The systemic inflammatory response is accompanied by the formation of ROS, which are normally neutralized by antioxidants.…”

“…7,15 The systemic inflammatory response is accompanied by the formation of ROS, which are normally neutralized by antioxidants. 12 However, hemorrhagic shock-induced mitochondrial dysfunction causes a shift of the balance toward increased ROS production over antioxidant neutralization capacity, which leads to cell apoptosis and tissue damage. 12 Additional therapeutic interventions are warranted to improve the success rate of the current treatment strategies to restore microcirculatory perfusion following hemorrhagic shock and fluid resuscitation.…”

“…12 However, hemorrhagic shock-induced mitochondrial dysfunction causes a shift of the balance toward increased ROS production over antioxidant neutralization capacity, which leads to cell apoptosis and tissue damage. 12 Additional therapeutic interventions are warranted to improve the success rate of the current treatment strategies to restore microcirculatory perfusion following hemorrhagic shock and fluid resuscitation. Hence, the aim of this review was to provide an overview of the effect of non-fluid-based therapeutic interventions, given in addition to fluid resuscitation, on microcirculatory perfusion following experimental hemorrhagic shock compared to untreated, with fluid resuscitated controls.…”

A Combination Treatment Strategy for Hemorrhagic Shock in a Rat Model Modulates Autophagy

“…Our experiments using a rat model of hemorrhagic shock injury (HI) demonstrated that in the absence of volume replacement, a protracted metabolic homeostasis may be achieved using agents that potentiate cellular energetics (5)(6)(7). Cellular energetics is an important determining factor in maintaining homeostatic balance (7)(8)(9). Our studies unequivocally showed that the naturally occurring SIRT1 activator, resveratrol (RSV), can prolong survival in experimental rats following HI in the absence of fluid resuscitation (5).…”

Immune and metabolic alterations following trauma and sepsis – An overview

“…Raju and colleagues tested oxygen consumption rate in splenocytes isolated from rats following hemorrhagic shock and demonstrated a decline in splenocyte mitochondrial function [21]. They also show an increased inflammatory response in splenocytes of rats subjected to hemorrhagic shock when compared to Sham controls.…”