TY - JOUR
T1 - Post-exposure administration of diazepam combined with soluble epoxide hydrolase inhibition stops seizures and modulates neuroinflammation in a murine model of acute TETS intoxication
AU - Vito, Stephen T.
AU - Austin, Adam T.
AU - Banks, Christopher N.
AU - Inceoglu, Bora
AU - Bruun, Donald A.
AU - Zolkowska, Dorota
AU - Tancredi, Daniel J
AU - Rogawski, Michael A
AU - Hammock, Bruce D.
AU - Lein, Pamela J
PY - 2014/12/1
Y1 - 2014/12/1
N2 - Tetramethylenedisulfotetramine (TETS) is a potent convulsant poison for which there is currently no approved antidote. The convulsant action of TETS is thought to be mediated by inhibition of type A gamma-aminobutyric acid receptor (GABAAR) function. We, therefore, investigated the effects of post-exposure administration of diazepam, a GABAAR positive allosteric modulator, on seizure activity, death and neuroinflammation in adult male Swiss mice injected with a lethal dose of TETS (0.15mg/kg, ip). Administration of a high dose of diazepam (5mg/kg, ip) immediately following the second clonic seizure (approximately 20min post-TETS injection) effectively prevented progression to tonic seizures and death. However, this treatment did not prevent persistent reactive astrogliosis and microglial activation, as determined by GFAP and Iba-1 immunoreactivity and microglial cell morphology. Inhibition of soluble epoxide hydrolase (sEH) has been shown to exert potent anti-inflammatory effects and to increase survival in mice intoxicated with other GABAAR antagonists. The sEH inhibitor TUPS (1mg/kg, ip) administered immediately after the second clonic seizure did not protect TETS-intoxicated animals from tonic seizures or death. Combined administration of diazepam (5mg/kg, ip) and TUPS (1mg/kg, ip, starting 1h after diazepam and repeated every 24h) prevented TETS-induced lethality and influenced signs of neuroinflammation in some brain regions. Significantly decreased microglial activation and enhanced reactive astrogliosis were observed in the hippocampus, with no changes in the cortex. Combining an agent that targets specific anti-inflammatory mechanisms with a traditional antiseizure drug may enhance treatment outcome in TETS intoxication.
AB - Tetramethylenedisulfotetramine (TETS) is a potent convulsant poison for which there is currently no approved antidote. The convulsant action of TETS is thought to be mediated by inhibition of type A gamma-aminobutyric acid receptor (GABAAR) function. We, therefore, investigated the effects of post-exposure administration of diazepam, a GABAAR positive allosteric modulator, on seizure activity, death and neuroinflammation in adult male Swiss mice injected with a lethal dose of TETS (0.15mg/kg, ip). Administration of a high dose of diazepam (5mg/kg, ip) immediately following the second clonic seizure (approximately 20min post-TETS injection) effectively prevented progression to tonic seizures and death. However, this treatment did not prevent persistent reactive astrogliosis and microglial activation, as determined by GFAP and Iba-1 immunoreactivity and microglial cell morphology. Inhibition of soluble epoxide hydrolase (sEH) has been shown to exert potent anti-inflammatory effects and to increase survival in mice intoxicated with other GABAAR antagonists. The sEH inhibitor TUPS (1mg/kg, ip) administered immediately after the second clonic seizure did not protect TETS-intoxicated animals from tonic seizures or death. Combined administration of diazepam (5mg/kg, ip) and TUPS (1mg/kg, ip, starting 1h after diazepam and repeated every 24h) prevented TETS-induced lethality and influenced signs of neuroinflammation in some brain regions. Significantly decreased microglial activation and enhanced reactive astrogliosis were observed in the hippocampus, with no changes in the cortex. Combining an agent that targets specific anti-inflammatory mechanisms with a traditional antiseizure drug may enhance treatment outcome in TETS intoxication.
KW - Benzodiazepine
KW - Diazepam
KW - Neuroinflammation
KW - Seizure
KW - Soluble epoxide hydrolase
KW - Tetramethylenedisulfotetramine
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UR - http://www.scopus.com/inward/citedby.url?scp=84912107543&partnerID=8YFLogxK
U2 - 10.1016/j.taap.2014.10.001
DO - 10.1016/j.taap.2014.10.001
M3 - Article
C2 - 25448683
AN - SCOPUS:84912107543
VL - 281
SP - 185
EP - 194
JO - Toxicology and Applied Pharmacology
JF - Toxicology and Applied Pharmacology
SN - 0041-008X
IS - 2
ER -