Recovery of Behavioral and Physiological Function In Vivo
Fully adult spinal-injured guinea pigs were the first test subjects for PEG application. We documented the loss and recovery of nerve impulse conduction through the lesion by SSEPs (Fig. 26). The CTM behavior was used to index functional loss and recovery (Fig. 10). These studies began with a topical application of PEG to the exposed spinal cord lesion at various times after spinal cord injury. Electrophysiological and quantitative behavioral records were obtained from each animal prior to a standardized spinal cord compression/contusion injury, immediately after the injury, and at various times after that for 1 month. The constant displacement injury (Blight 1990) was adjusted so that 100% of the control population never recovered SSEP conduction, and spontaneous recovery of the CTM occurred in less than 20% of the population of injured animals. We first applied PEG roughly 15 min after injury. This determined if the striking and rapid changes observed in vitro could be duplicated in vivo. In these studies, an aqueous PEG solution similar to that used in vitro was applied to the exposed spinal cord injury following a hemilaminectomy, durotomy, and lesioning. This was also applied for about 2 min, after which the PEG solution was aspirated and the region thoroughly lavaged with isotonic saline. In additional studies, it was found that direct application of 50% PEG to uninjured spinal cord parenchyma for extended periods exceeding 5 min produced damage to the spinal cord tissues (Fig. 31).
KeywordsSpinal Cord Spinal Cord Injury Topical Application Spinal Cord Lesion Spinal Cord Tissue
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