Studies on experimental brain edema II. The effects of various glucocorticoids on experimental brain edema

Although glucocorticoids have received wide acceptance in neurosurgery, the mechanisms by which they affect cerebral edema are still obscure. The dose equivalent of each glucocorticoid preparation is also uncertain. Only dose equivalents determined by antiinflammatory effects on granulation, have been used in the treatment of brain edema. The author attempted to determine the dose equivalent of each glucocorticoid according to its antiedema effect in cerebral tissue. Cold induced brain edema was produced by touching a metal probe at the temperature of -90℃ to the right parietal region of rats for 3 min. 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 either 3 hours prior to or after, the cold injury. The animals were sacrificed 24 hours after injury and the grade of brain edema was determined by the changes in water content of the brain tissue. For this purpose, the author used tritiated water in a new method which was described in Part I of this paper. In the group of animals which were treated with prednisolone, dexamethasone or betamethasone, the water content decreased significantly from the non-treated value to almost control value. In the animals treated with hydrocortisone or methylprednisolone, the water content did not change significantly. In animals treated with double doses of hydrocortisone (32 mg/Kg) or methylprednisolone (6.4 mg/Kg), antiedema effects were obtained. From these results, the author concluded that the dose equivalent of each glucocorticoid for the treatment of brain edema was as follows; hydrocortisone : prednisolone : methylprednisolone : dexamethasone : betamethasone = 40:4:8:1:1