Erythromycin induced neuroprotection during prolonged deep hypothermic circulatory arrest in an acute porcine model

Methods Piglets were treated with erythromycin (25 mg/kg, iv) (n = 8) or vehicle (n = 6) and subjected to 75 minutes of DHCA at 18°C, 12 hours after pretreatment. Three served as normal controls. After gradual rewarming, treatment animals were sacrificed and brains were perfusion-fixed and cryopreserved. Motor cortex was dissected from the left hemisphere and paraffin embedded for histologic staining with hematoxylin and eosin (HE). To assess neuronal damage, HE-stained paraffin sections (10 μm) were examined by light microscopic examination at x400 magnification. Layer V of the motor cortex was counted. Neuronal injury was recorded when there was evidence of eosinophilic cytoplasm, cytoplasmic vacuolation, cell body shrinkage or nuclear pyknosis. Neuronal injury was scored on a scale of 0-5.