Antiepileptic effects of exogenous β-hydroxybutyrate on kainic acid-induced epilepsy

Abstract

The aim of the present study was to explore the potential anticonvulsant effects of β-hydroxybutyrate (BHB) in a kainic acid (KA)-induced rat epilepsy model. The KA-induced rat seizure model was established and BHB was administrated intraperitoneally at a dose of 4 mmol/kg 30 min prior to KA injection. Hippocampal tissues were then obtained 1, 3 and 7 days following KA administration, following which the expression levels of neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP) were measured using a double immunofluorescence labeling method. In addition, the contents of glutathione (GSH), γ-aminobutyric acid (GABA) and ATP were measured using ELISA. Pretreatment with BHB markedly increased the expression of NSE after KA injection compared with that in the normal saline (NS) + KA group, suggesting that the application of BHB could alleviate neuronal damage in rats. The protective effect of BHB may be associated with suppressed inflammatory responses, which was indicated by the observed inhibition of GFAP expression in rats in the BHB + KA group compared with that in the NS + KA group. It was also found that GSH and GABA contents were notably increased after the rats were pretreated with BHB compared with those in the NS + KA group. To conclude, the application of exogenous BHB can serve as a novel therapeutic agent for epilepsy.

Keywords: epilepsy; kainic acid; neuron damage; β-hydroxybutyrate.

Copyright: © Si et al.

Figures

Figure 1

Immunofluorescence staining of NSE and GFAP in the hippocampus of rats 1 day after KA injection. Green signals represent NSE, red signals represent GFAP and the blue signals represent the cell nuclei stained with DAPI. Scale bar, 50 µm. NSE, neuron specific enolase; GFAP, glial fibrillary acidic protein; BHB, β-hydroxybutyrate; KA, kainic acid; NS, normal saline.

Figure 2

Immunofluorescence staining of NSE and GFAP in the hippocampus tissues of rats 3 days after KA injection. Green signals represent NSE, red signals represent GFAP and blue signals represent the cell nuclei stained with DAPI. Scale bar, 50 µm. NSE, neuron specific enolase; GFAP, glial fibrillary acidic protein; BHB, β-hydroxybutyrate; KA, kainic acid; NS, normal saline.

Figure 3

Immunofluorescence staining of NSE and GFAP in the hippocampus tissues of rats 7 days after KA injection. Green signals represent NSE, red signals represent GFAP and blue signals represent the cell nuclei stained with DAPI. Scale bar, 50 µm. NSE, neuron specific enolase; GFAP, glial fibrillary acidic protein; BHB, β-hydroxybutyrate; KA, kainic acid; NS, normal saline.

Figure 4

Expression levels of NSE and GFAP in the hippocampal tissue. (A) NSE expression 1, 3 and 7 days after different treatments. KA administration decreased the NSE expression (D1 and D3), whilst BHB alleviated this reduction (D1). (B) GFAP expression 1, 3 and 7 days after different treatments. KA administration increased the GFAP expression but pretreatment with BHB significantly reduced GFAP expression (D3 and D7). aP<0.05 vs. NS; bP<0.05 vs. NS+KA; cP<0.05 vs. BHB+KA; #P<0.05 vs. D1 NS + KA; *P<0.05 vs. D3 NS + KA; OD, optical density; NSE, neuron specific enolase; GFAP, glial fibrillary acidic protein; BHB, β-hydroxybutyrate; KA, kainic acid; NS, normal saline.

Figure 5

GSH contents in the hippocampal tissues as measured using ELISA after 1, 3 and 7 days of different treatments. GSH contents were decreased after KA administration whilst pretreatment with BHB alleviated this reduction (D1 and D7). aP<0.05 vs. NS; bP<0.05 vs. NS+KA; BHB, β-hydroxybutyrate; KA, kainic acid; NS, normal saline; GSH, glutathione.

Figure 6

GABA contents in the hippocampal tissues as measured using ELISA after 1, 3 and 7 days of different treatments. GABA contents were reduced by KA administration whilst BHB pretreatment relieved this reduction (D1, D3 and D7). aP<0.05 vs. NS; bP<0.05 vs. NS + KA; cP<0.05 vs. BHB + KA; GABA, gamma-aminobutyric acid; BHB, β-hydroxybutyrate; KA, kainic acid; NS, normal saline.