The Expression of BDNF mRNA in the Hippocampal Formation after Febrile Seizure

Sohn, Bo Ra; Kim, Young Hoon; Whang, Kyung Tai

Abstract

PURPOSE: Neuronal damage induced by febrile seizure(FS) has been implicated in the pathogenesis of medial temporal sclerosis, the pathologic hallmark of temporal lobe epilepsy. Recent data indicate that prolonged FSs induce transient structural changes of some hippocampal pyramidal neurons and long-term functional changes of hippocampal circuitry. In this study we have investigated the expression of brain-derived neurotrophic factor(BDNF) in the hippocampal formation after FSs with in situ hybridization histochemistry using riboprobe.
METHODS
FSs were induced in 21 day-old male Sprague-Dawley rats(five rats for each group), which had a mean weight of about 100g. Exposure to hyperthermia was achieved by maintaining the water in the beaker at a temperature of 45 degrees C by pacing it in a temperature-controlled water bath. The rats were decapitated at appropriate times(0 hr, 30 min, 1 hr, 2 hr, 3hr, 6 hr, 12 hr and 24 hr) after FSs. In situ hybridization histochemistry was performed. The probe used in these studies were riboprobe complementary to the sequence 641-729 of rat BDNF.
RESULTS
The induction of BDNF mRNA was observed in the dentate gyrus at 30 min after FSs. The expression in the dentate gyrus was gradually increased, peaked at 3 hr after FSs, and almost returned to basal level at 24 hr after FSs. The significant induction of BDNF mRNA was also observed in the CA3 area of hippocampus from 2 hr to 3 hr after FSs.
CONCLUSION
These observations suggest that BDNF is the gene whose expression can be altered by FSs and these gene might be related to pathologic alterations after FSs.