Relationship between therapy of radioactive cerebral edema with methylprednisolone and dexamethasone and transcription level of epidermal growth factor receptor 1

Objective To study the effect of methylprednisolone (MP) and dexamethasone (DXM) on radioactive cerebral edema and the transcription level of epidermal growth factor receptor 1 (erb-B1). Methods One hundred male Wistar rats were divided into 5 groups randomly (n=20). Group A was irradiated in combination with 30 mg/kg MP, group B was irradiated in combination with 10 mg/kg MP, group C was irradiated in combination with 5 mg/kg DXM, group D was irradiated without glucocorticoid (GC), and group E served as normal control. Glioma cells were planted into brains of rats in groups A, B, C, D and E, and the animals in groups A, B, C, and D were given irradiateion of 60Co after 15 days. All groups were give GC or normal saline 3 days before and 6 days after irradiation. The water content of the brains and the transcription level of erb-B1 were measured 6 days after irradiation. Results The water content of the rats brain: A: 0.758 8±0.015 9, B: 0.766 9±0.017 4, C: 0.796 5±0.019 7, D: 0.828 3±0.021 6, E: 0.727 0±0.011 3. There was significant difference between group D, E and group A, B, C (P 0.05). The level of erb-B1 mRNA: A: 0.739 1±0.041 5, B: 0.741 0±0.034 4, C: 0.775 4±0.054 6, D: 0.802 1±0.055 8, E: 0.715 6±0.059 2. There were significant difference between group D, E and group A, B, C (P 0.05). Conclusion MP and DXM can both protect the radiation-induced injury and brain edema changes by inhibiting the transcription level of erb-B1 mRNA in rats, and the MP is more efficient than DXM. Key words: Radioactive cerebral edema; Glioma; Methylprednisolone; Dexamethasone; erb-B1