Systemic hypothermia following compression injury of rat spinal cord: reduction of plasma protein extravasation demonstrated by immunohistochemistry

Abstract

Systemic hypothermia has neuroprotective effects in experimental models of central nervous system ischemia caused by vascular occlusions. The present study addresses the question as to whether systemic hypothermia can influence the extravasation of plasma proteins following severe spinal cord compression trauma using immunohistochemistry to identify the plasma proteins albumin, fibrinogen and fibronectin. Fifteen rats were assigned to one of three groups and received either thoracic (T) laminectomy or severe spinal cord compression trauma of the T8-9 segment. One group comprised laminectomized animals without compression trauma submitted to a hypothermic procedure in which the core temperature was reduced from 38 degrees to 30 degrees C. The two trauma groups were either submitted to the same hypothermic procedure or kept normothermic during the corresponding time. All animals were killed 24 h following the surgical procedure. The normothermic and hypothermic trauma groups had indications of marked extravasation of albumin, fibrinogen and fibronectin at the site of the injury (T8-9). There was also pronounced extravasation in the cranial and caudal peri-injury zones (T7 and T10) of normothermic injured rats but, with few exceptions, not in the hypothermic ones with the same degree of compression. By measuring the cross-sectional area of the peri-injury zones we found in the hypothermic trauma group a significant reduction of the expansion compared with that present in normothermic injured rats. Our study thus indicates that hypothermia reduces the extravasation of the plasma proteins albumin, fibrinogen and fibronectin following spinal cord compression in the rat. Such a reduction may contribute to neuroprotective effects exerted by hypothermia.

Post-traumatic moderate systemic hypothermia reduces TUNEL positive cells following spinal cord injury in rat

“…Previous studies have demonstrated various mechanisms underlying the effectiveness of hypothermia in mitigating SCI, such as decrease of vasogenic edema to reduce extravasation of fibrinogen and fibronectin, 23 inhibition of polymorphonuclear leukocyte infiltration and accumulation, 24 and suppression of signaling impairment in the white matter 25,26 or neuronal impairment in the gray matter. 27 The results of the present study showed that at 24 and 72 h after injury, the numbers of TPC in injured spinal cord were high at the center of injury, but low in regions 5 and 10 mm rostral and caudal to the center.…”

The Ryk Receptor Is Expressed in Glial and Fibronectin-Expressing Cells after Spinal Cord Injury

“…[42][43][44][45] For this reason, we sought to evaluate by 14 dpi, when we observed that fibronectin immunolabeling in the injured tissue was clearly…”

“…Several reports have demonstrated the presence of fibronectin in the injury core, even in non-penetrating injuries where meningeal fibroblast invasion and proliferation are minimal. [42][43][44][45] Different sources have been proposed for this fibronectin + scar, including vascular extravasation of plasma fibronectin. 42,45 However, this intriguing issue has not been completely explored as, for example, there are meningeal-like cells that surround the blood vessels in the CNS, but the extent to which they participate in CNS injuries is not yet clear.…”

“…[42][43][44][45] Different sources have been proposed for this fibronectin + scar, including vascular extravasation of plasma fibronectin. 42,45 However, this intriguing issue has not been completely explored as, for example, there are meningeal-like cells that surround the blood vessels in the CNS, but the extent to which they participate in CNS injuries is not yet clear. 71 Moreover, it has been shown that there is an increase in the perivascular cells expressing fibroblast markers after a contusive injury to the rat spinal cord.…”

Hypothermic Treatment for Acute Spinal Cord Injury

“…In terms of SCI, published data have shown that relatively mild levels of hypothermia introduced after a traumatic or compressive SCI provides some degree of improvement in function and reduces the histopathological damage [22,[25][26][27][28][29][30][31][32][33][34][35][36][37]. In clinically relevant SCI studies, mild reductions in temperature have been shown to be protective, whereas mild elevations (hyperthermia) have been reported to worsen outcome [38][39][40].…”