Novel Probucol Analogue, 4,4'-Diselanediylbis (2,6-Di- tert -Butylphenol), Prevents Oxidative Glutamate Neurotoxicity In Vitro and Confers Neuroprotection in a Rodent Model of Ischemic Stroke.

Oxidative glutamate toxicity is regarded as one of the injurious mechanisms associated with ischemic stroke, which represents a major health problem and requires improved pharmacological treatments. We designed and synthesized two new probucol analogues [2,6-di- tert -butyl-4-selenocyanatophenol ( C1 ) and 4,4'-diselanediylbis (2,6-di- tert -butylphenol) ( C2 )] and investigated their effects against glutamate-induced neuronal oxidative toxicity in vitro in cultured HT22 cells, compared with their parental compound (probucol). In addition, C2 , which exhibited the lowest toxicity, was investigated in an in vivo rodent model of ischemic stroke. Glutamate caused concentration- and time-dependent cytotoxicity in HT22 neuronal cells, which was preceded by increased levels of oxidants and depletion of the antioxidant glutathione. The analogues ( C1 and C2 ), but not probucol, significantly decreased the levels of oxidants (including mitochondrial superoxide anion and lipid reactive oxygen species (ROS)) and protected against glutamate-induced cytotoxicity. In the in vivo model of ischemic stroke, which was based on central injections of the vasoconstrictor agent endothelin-1 (800 pmol/site), C2 (20 or 50 mg/kg/day, intraperitoneally, for 4 consecutive days after stroke) displayed significant beneficial effects against ischemic injury in vivo , improving rats' motor-related behavioral skills and decreasing stroke-related striatal gliosis. This is the first study to design, synthesize, and present a probucol analogue ( C2 ) with in vivo beneficial effects against ischemic stroke. This novel compound, which was able to mitigate glutamate-induced oxidative toxicity in vitro , represents a promising neuroprotective drug.