Visualization of protein aggregation in nerve cells after ischemia/reperfusion by ubiquitin immunohistochemistry and impregnative Nauta method

Using ubiquitin immunohistochemistry and impregnative Nauta method we demonstrated that ubiquitin positivity and Nauta positivity in the neurons affected with ischemic injury in the lumbosacral spinal cord of rabbits and dogs may be of the same origin. Increased number of ubiquitin-positive aggregates was found in the cytoplasm of neurons in the intermediate zone and lamina IX of ventral horns of spinal cord in rabbits after 30 min of ischemia followed by 24 h lasting reperfusion. Nauta-positive, flocculent, intracytoplasmic, dark clusters appeared in the same localization in the canine lumbosacral spinal cord neurons after 30 min of ischemia and 24 h of reperfusion. Ubiquitin aggregates and Nauta-positive dark clusters in the injured spinal cord neurons could be the first light microscopic signs of slow neuronal death following spinal cord ischemia and reperfusion.