LPS-induced endotoxic shock does not cause early brain edema formation – An MRI study in rats
Objective and design:
Early microcirculatory failure is assumed as a key factor in the development of a septic encephalopathy. However, brain edema is also a common finding in sepsis syndromes possibly interfering with the vasoregulative mechanisms of the brain. We assessed the occurrence of brain edema in a rat model of endotoxic shock.
Material and subjects:
Eleven mechanically ventilated male CD-rats.
Intravenous application of 5 mg/kg LPS (n = 8) or vehicle (n = 3).
Apparent diffusion coefficient (ADC) and T2-relaxation time (T2RT) were quantified on cerebral MRI at baseline and repeatedly for up to 3.5 h after LPS-injection. Change in blood pressure was compensated with norepinephrine. Brain water content was quantified using the wet/dry method.
All LPS-treated rats developed endotoxic shock. No significant difference in T2RT or ADC was detectable before and after LPS-injection (T2RT: baseline 60.33 ± 1.21; after 3.5 h 60.15 ± 0.59; ADC: baseline 6.86 ± 0.51; after 3.5 h 6.75 ± 0.33). Post-mortem analysis did not indicate a difference in brain water content between septic and non-septic animals.
Reports of early microcirculatory failure seem not to be related to the occurrence of early (≤3.5 h) brain edema.
Keywords:Shock Sepsis Brain edema MRI Rat Lipopolysaccharide
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