Calbindin D-28k is expressed in the microvascular basal lamina in the ventral horn at early time after transient spinal cord ischemia in the rabbit

Much evidence has been accumulated that the increased expression of calbindin D-28k (CB) is involved in the blockade of calcium-evoked excitotoxicity in cerebral ischemia. We investigated the expression of CB in the basal lamina of microvessels in the ventral horn of the rabbit spinal cord after transient spinal cord ischemia. Spinal cord sections at the level of L7 were immunostained using monoclonal antibody raised against CB at light and electron microscopic levels. CB immunoreactivity was detected in the basal lamina of microvessels at 30 min after ischemic insult. By 3 h after ischemia, CB immunoreactivity was increased in the basal lamina of the microvessels. CB immunoreactivity began to decrease at 6 h after ischemia and nearly disappeared at 48 h after ischemic insult. For calcium detection in the blood vessels of spinal cord, we conducted an alizarin red staining. Alizarin red reactivity was detected in some microvessels at 3 h after ischemic insult. Our results suggest that the ectopic expression of CB in the microvascular basal laminae may be associated with the buffering of calcium in the endothelial cells of microvessels after ischemic damage.