Gastrodin Attenuates Pentylenetetrazole-Induced Seizures by Modulating the Mitogen-Activated Protein Kinase-Associated Inflammatory Responses in Mice

Abstract

Gastrodin, the major component isolated from the rhizome of the Chinese traditional medicinal herb Gastrodia elata ("Tianma"), has a long history in the treatment of epilepsy and other neurological disorders. However, the molecular mechanisms are not clear. Here, we found that gastrodin ameliorated pentylenetetrazole (PTZ)-induced epileptic seizures with improvement of the electroencephalographic pattern in mice. Further studies demonstrated that gastrodin decreased the levels of the pro-inflammatory cytokines interleukin-1β and tumor necrosis factor-α while increasing interleukin-10, an anti-inflammatory cytokine in the brain. Furthermore, gastrodin attenuated the PTZ-induced microglial activation along with inhibition of mitogen-activated protein kinases, cAMP response element binding protein, and NF-κB. Our data suggest that gastrodin attenuates seizures by modulating the mitogen-activated protein kinase-associated inflammatory responses.

Keywords: CREB; Epilepsy; Gastrodin; IL-10; IL-1β; MAPK; NF-κB; TNF-α.

Fig. 1

Gastrodin reduced the seizure score and increased the latency to seizures. A Average seizure scores (n = 15; *P < 0.05 vs EP-NS group). B, C Average latency to myoclonic jerks (B) and generalized tonic-clonic seizures (C) (n = 15; **P < 0.01 vs EP-NS group; ^$ P < 0.05, ^$$ P < 0.01 vs 50 mg/kg EP-GS group; ^# P < 0.05, ^## P < 0.01 vs 100 mg/kg EP-GS group).

Fig. 2

Representative EEG recordings. A Normal EEG from an awake mouse with saline injection. B EEG pattern from a model mouse during a persistent ictal episode showing polyspike discharges in both hemispheres. C Gradually stabilizing EEG pattern from a model mouse given gastrodin (200 mg/kg) followed by injection of PTZ (35 mg/kg), which induced a re-seizure.

Fig. 3

Gastrodin inhibited the expression of interleukin (IL)-1β and tumor necrosis factor α (TNF-α), and increased the expression of IL-10 in the cortex of the pentylenetetrazole mouse model. A Western blots and B quantitative analysis of bands in A (n = 3; ^# P < 0.05, ^## P < 0.01 vs Ctrl; ^* P < 0.05, ^** P < 0.01 vs EP-NS).

Fig. 4

Gastrodin inhibited IL-1β expression in CD11b⁺ microglia in the temporal lobe of PTZ model mice. In the EP-NS group, IL-1β was found exclusively in activated CD11b⁺ microglia in cortex (arrows). IL-1β expression was remarkably decreased in the EP-GS group, and a few IL-1β⁺ cells did not overlap with CD11b⁺ cells (arrows). Scale bar, 20 µm.

Fig. 5

Gastrodin inhibited MAP kinase phosphatase-1 (MKP-1)/mitogen-activated protein kinase signaling in PTZ model mice. A and C, Western blots; B and D, quantitative analysis (n = 3; ^# P < 0.05, ^# P < 0.01 vs Ctrl; ^* P < 0.05, ^** P < 0.01 vs EP-NS group).

Fig. 6

Gastrodin suppressed the PTZ-induced phosphorylation of IκB-α and CREB, as revealed by Western blotting (n = 3; ^# P < 0.05 vs Ctrl group; ^* P < 0.05, ^** P < 0.01 vs EP-NS group).