[Effect of various kinds of glucocorticoids on experimental brain edema (author's transl)].

Although the effectiveness of glucocorticoids for the treatment of cerebral edema has been widely accepted in neurosurgical practice, but its mechanism is still obscure. Also the dose equivalent of various kinds of glucocorticoid preparation is still uncertain. Only the dose equivalent determined by the test examining an antiinflammatory effect on a growth of glanulation, has been applied for the treatment of brain edema. The authors attempted to establish the dose equivalent of each kinds of glucocorticoid for the treatment of cerebral edema. Cold induced cerebral edema was produced by touching a metal probe at the temperature of -90 degrees C for 3 minutes on the right parietal cortex of rat brain. Hydrocortisone (16 mg/kg), prednisolone (3.2 mg/kg), methylprednisolone (3.2 mg/kg), dexamethasone (0.8 mg/kg) and betamethasone (0.8 mg/kg) were administered at the time of 3 hours prior or after the cold injury. The animals were sacrificed 24 hours after injury and the grade of brain edema was determined by the changes of water content in the brain tissue. For this purpose, the authors developed a new method of measuring water content in the brain tissue using tritiated water and a liquid scintillation counter. In the group of animals which were treated with prednisolone, dexamethasone or betamethasone, the water content was significantly decreased compared to the value of non-treated animals. But in the animals treated with hydrocortisone or methylprednisolone, no significant changes of the water content was observed. But in the animals treated with double doses of hydrocortisone (32 mg/kg) or methylprednisolone (6.4 mg/kg), cerebral edema was improved significantly. From these results the authors concluded that the dose equivalent of each kinds of glucocorticoid for the treatment of the brain edema was as follows: hydrocortisone: prednisolone: methylprednisolone: dexamethasone: betamethasone = 40 : 4 : 8 : 1 : 1.