The role of the monosialoganglioside, GM₁, as a neuroprotectant in an experimental model of cardiopulmonary bypass and hypothermic circulatory arrest

Twelve male dogs were placed on closed-chest cardiopulmonary bypass, subjected to 2 h of HCA at 18°C, and rewarmed to 37°C on closed-chest cardiopulmonary bypass. All animals were mechanically ventilated and monitored for 20 h before extubation and survived for 3 days. Group 1 dogs (n = 6) were pretreated with GM₁, 30 mg/kg/24 h for 3 days before HCA, and received continuous infusion of GM₁ during the procedure and 30 mg/kg/24 h for 3 days after HCA. Group 2 dogs (n = 6) received vehicle only. With a species-specific behavior scale that yielded a neurodeficit score ranging from 0% (normal) to 100% (brain dead), all animals were neurologically assessed every 12 h by two observers. After death at 72 h, brains were examined by glutamate receptor autoradiography and by histologic examination for patterns of selective neuronal necrosis and were scored blindly from 0 (normal) to 100 (severe injury). These results provide evidence of a role for GE in the development of HCA-induced brain injury and suggest that monosialogangliosides may have a neuroprotective effect in prolonged periods of HCA.