Neuroprotective effects of HU-211 on brain damage resulting from soman-induced seizures

Neuroprotective effects of HU-211 (dexanabinol), a synthetic nonpsychotropic analog of tetrahydrocannabinol, on brain damage resulting from soman-induced seizures were examined in male Sprague-Dawley rats challenged with 1.6 LD50 soman. At 5 or 40 min after onset of seizures, the rats were given an intraperitoneal injection of 25 mg/kg HU-211. All rats that received soman showed electrocorticographic (ECoG) evidence of sustained seizures and status epilepticus for 4-6 hr. HU-211 had no effect on either the strength or duration of seizure activity. Administration of HU-211 at 5 min after seizure onset reduced median lesion volume 86% (as assessed by microtubule-associated protein 2 (MAP2)-negative staining), and when administered 40 min post-onset, the reduction in necrosis was 81.5% despite the presence of continuous seizures for 4-5 hr. These observations were corroborated by hemotoxylin and eosin (H&E) histopathological assessment that showed a significant reduction in piriform cortical neuronal damage in HU-211-treated animals. It is concluded that HU-211 provides considerable neuroprotection against brain damage produced by soman-induced seizures.