The Effects of Delayed Fluid Resuscitation on Lung Oxidative Stress and Antioxidant Vitamin Levels in Controlled Hemorrhagic Shock: An Experimental Study

Abstract

We aimed to determine the effects of delayed fluid resuscitation on the lung oxidative stress and antioxidant vitamin levels in a rat model of controlled hemorrhagic shock (HS). Male Wistar rats were exposed to controlled HS via arterial catheterization to reduce mean arterial pressure (MAP) to 40 mmHg over 10 minutes. Two groups were constituted according to resuscitation time: early (n=6) and delayed (n=5), respectively resuscitated 30 or 90 minutes after HS. A control group (n=5) was subjected to catheterization only. Intravenous fluid resuscitation was done with Ringer lactate solution. After 24 hours, bronchoalveolar lavage (BAL) was performed and the lungs were harvested for biochemical, cytological and histopathological analyses. Lipid peroxidation (as MDA), reduced glutathione (GSH), glutathione peroxidase (GSH-Px) and vitamin A, vitamin C and vitamin E levels were measured in both BAL fluid (BALF) and lung homogenate. Lung tissue GSH-Px and vitamin E levels are increased in both HS groups compared to the control group. No significant differences were found in MDA, GSH, vitamin A and vitamin C BALF levels among all groups, except for GSH-Px (p=0.007). Intracellular antioxidants, especially GSH-Px and vitamin E, increase in the lungs of rats (in both HS groups), possibly due to increased oxidative stress and increased physiological requirements after HS and resuscitation.