Effect of Methylprednisolone on Experimental Brain Edema in Magnetic Resonance Imaging

Magnetic resonance imaging has been used for evaluating of a brain edema in experimental animals to assess cytotoxic and vasogenic edema by the apparent diffusion coefficient (ADC) and T2 imaging. This paper brings information about the effectiveness of methylprednisolone (MP) on experimental brain edema. A total of 24 rats were divided into three groups of 8 animals each. Rats with cytotoxic/intracellular brain edema induced by water intoxication were assigned to the group WI. These rats also served as the additional control group CG when measured before the induction of edema. A third group (WIMP) was intraperitoneally administered with methylprednisolone 100 mg/kg during water intoxication treatment. The group WI+MP was injected with methylprednisolone 50 mg/kg into the carotid artery within two hours after the water intoxication treatment. We evaluated the results in four groups. Two control groups (CG, WI) and two experimental groups (WIMP, WI+MP). Rats were subjected to MR scanning 24 h after edema induction. We observed significantly increased ADC values in group WI in both evaluated areas – cortex and hippocampus, which proved the occurrence of experimental vasogenic edema, while ADC values in groups WIMP and WI+MP were not increased, indicating that the experimental edema was not developed and thus confirming the protective effect of MP.

Study of cytokines content and gangliosides metabolism at experimental brain edema

The content of cytokines, and gangliosides metabolism, and the quantity of lipid peroxidation products were studied at experimental brain edema. Data obtained show increase the level of proinflammatory cytokins and decrease the level of antiinflammatory cytokines during development of brain edema. Along with this we reveal the accumulation of lipid peroxidation products (diene conjugates, hydroperoxides, and malonic dialdehyde). Each fraction of gangliosides decreased, but the product of their hydrolytic dissociation sphingosine increased at experimental brain edema.

Cerebral blood flow and glucose metabolism in experimental brain edema

✓ The relationship between cerebral blood flow (CBF) and cerebral metabolic rate of glucose (CMR gl) in the white matter was studied in a plasma infusion model of vasogenic edema in cats. Local CBF, as determined by iodoantipyrine testing, was found to be significantly decreased in edematous white matter (mean ± standard error of the mean: 17.3 ± 1.5 ml/100 gm/min) when compared with CBF in the contralateral control white matter (24.8 ± 1.8 ml/100 gm/min). When the values for edematous brain were corrected for dilution, however, the local CBF averaged 25.3 ± 1.7 ml/100 gm/min, which was similar to the control value. Local CMRgl was found to be significantly increased in plasma-infused white matter (16.3 ± 2.2 µmol/100 gm/min) compared with that in control white matter (10.7 ± 1.3 µmol/100 gm/min). This difference remained, despite correction for dilution and recalculation of local CMRgl values based on altered kinetic constants found in edematous brain. A similar increase in local CMRgl was noted with saline-infusion edema. It is concluded that the increased tissue water level does not alter CBF, but does induce an increase in anaerobic metabolism.