Intravenous Administration of Human Umbilical Cord Blood Reduces Neurological Deficit in the Rat after Traumatic Brain Injury

Haemopoiesis is sustained by two main cellular components, the haematopoietic cells (HSCs) and the mesenchymal progenitor cells (MPCs). MPCs are multipotent and are the precursors for marrow stroma, bone, cartilage, muscle and connective tissues. Although the presence of HSCs in umbilical cord blood (UCB) is well known, that of MPCs has been not fully evaluated. In this study, we examined the ability of UCB harvests to generate in culture cells with characteristics of MPCs. Results showed that UCB-derived mononuclear cells, when set in culture, gave rise to adherent cells, which exhibited either an osteoclast- or a mesenchymal-like phenotype. Cells with the osteoclast phenotype were multinucleated, expressed TRAP activity and antigens CD45 and CD51/CD61. In turn, cells with the mesenchymal phenotype displayed a fibroblast-like morphology and expressed several MPC-related antigens (SH2, SH3, SH4, ASMA, MAB 1470, CD13, CD29 and CD49e). Our results suggest that preterm, as compared with term, cord blood is richer in mesenchymal progenitors, similar to haematopoietic progenitors.

Controlled cortical impact models produce brain injury by using a pneumatic impactor to impact exposed brain. This study systematically examined the effects of varying magnitudes of controlled cortical impact to the rat brain on neurological, cardiovascular, and histopathological variables. As the magnitude of injury increased, the duration of suppression of somatomotor reflexes and the duration of chronic vestibular motor deficits increased. The blood pressure response was observed to depend on injury levels; a moderate injury level produced a hypotensive response while a high injury level produced an immediate brief hypertensive response followed by hypotension. Low injury levels produced no significant macroscopic or microscopic change, but higher injury levels produced cortical contusion and intraparenchymal hemorrhage which, with increasing survival time, evolved into necrotic changes and cavitation underlying the injury site. Also with high levels of injury, axonal injury was found throughout the brain-stem with the greatest concentration of injured axons occurring in the cerebellar peduncles and pontomedullary junction. These data demonstrate that controlled cortical impact in the rat reproduces many of the features observed in other experimental animal models. This model allows independent control of many mechanical loading parameters associated with traumatic brain injury. The controlled cortical impact rat model should be an effective experimental tool to investigators of traumatic brain injury.

The purpose of the present experiment was to examine the effectiveness of a modified rotarod test in detecting motor deficits following mild and moderate central fluid percussion brain injury. In addition, this investigation compared the performance of the rotarod task with two other commonly used measures of motor function after brain injury (beam-balance and beam-walking latencies). Rats were either injured with a mild (n = 14) or moderate (n = 8) level of fluid percussion injury or were surgically prepared but not injured (n = 8). All rats were assessed on all tasks for 5 days following their respective treatments. Results revealed that both the mild and moderate injury levels produced significant deficits in the ability of the animals to perform the rotarod task. Performance on the beam-balance and beam-walking tasks were not significantly impaired at the mild injury level. It was only at the moderate injury level that the beam-balance and beam-walking tasks detected deficits in motor performance. This result demonstrated that the rotarod task was a sensitive index of injury-induced motor dysfunction following even mild fluid percussion injury. A power analysis of the three tasks indicated that statistically significant group differences could be obtained with the rotarod task with much smaller sample sizes than with the beam-balance and beam-walking tasks. Performance on the rotarod, beam-walk, and beam-balance tasks were compared and evaluated by a multivariate stepdown analysis (multiple analysis of variance followed by univariate analyses of covariance). This analysis indicated that the rotarod task measures aspects of motor impairment that are not assessed by either the beam-balance or beam-walking latency. These findings suggest that compared to the beam-balance and beam-walking tasks, the rotarod task is a more sensitive and efficient index for assessing motor impairment produced by brain injury.