Role of acid-sensing ion channel 1a in the secondary damage of traumatic spinal cord injury.

OBJECTIVE: To determine the cellular and molecular mechanisms by which acid-sensing ion channel 1a (ASIC1a) plays its role in the secondary injury after traumatic spinal cord injury (SCI), and validate the neuroprotective effect of ASIC1a suppression in SCI model in vivo. BACKGROUND: Secondary damage after traumatic SCI contributes to the exacerbation of cellular insult and thereby contributes to spinal cord dysfunction. However, the underlying mechanisms remain largely unknown. Acidosis is commonly involved in the secondary injury process after the injury of central nervous system, but whether ASIC1a is involved in secondary injury after SCI is unclear. METHODS: Male Sprague-Dawley rats were subjected to spinal contusion using a weight-drop injury approach. Western blotting and immunofluorescence assays were used to observe the change of ASIC1a expression after SCI. The TUNEL staining in vivo as well as the cell viability and death assays in spinal neuronal culture were employed to assess the role of ASIC1a in the secondary spinal neuronal injury. The electrophysiological recording and Ca(2+) imaging were performed to reveal the possible underlying mechanism. The antagonists and antisense oligonucleotide for ASIC1a, lesion volume assessment assay and behavior test were used to estimate the therapeutic effect of ASIC1a on SCI. RESULTS: We show that ASIC1a expression is markedly increased in the peri-injury zone after traumatic SCI. Consistent with the change of ASIC1a expression in injured spinal neurons, both ASIC1a-mediated whole-cell currents and ASIC1a-mediated Ca(2+) entry are significantly enhanced after injury. We also show that increased activity of ASIC1a contributes to SCI-induced neuronal death. Importantly, our results indicate that down-regulation of ASIC1a by antagonists or antisense oligonucleotide reduces tissue damage and promotes the recovery of neurological function after SCI. CONCLUSION: This study reveals a cellular and molecular mechanism by which ASIC1a is involved in the secondary damage process after traumatic SCI. Our results suggest that blockade of Ca(2+) -permeable ASIC1a may be a potential neuroprotection strategy for the treatment of SCI patients.

Functional recovery in acute traumatic spinal cord injury after transplantation of human umbilical cord mesenchymal stem cells.

OBJECTIVE: Spinal cord injury results in loss of neurons, degeneration of axons, formation of glial scar, and severe functional impairment. Human umbilical cord mesenchymal stem cells can be induced to form neural cells in vitro. Thus, these cells have a potential therapeutic role for treating spinal cord injury. DESIGN AND SETTING: Rats were randomly divided into three groups: sham operation group, control group, and human umbilical cord mesenchymal stem cell group. All groups were subjected to spinal cord injury by weight drop device except for sham group. SUBJECTS: Thirty-six female Sprague-Dawley rats. INTERVENTIONS: The control group received Dulbecco's modified essential media/nutrient mixture F-12 injections, whereas the human umbilical cord mesenchymal stem cell group undertook cells transplantation at the dorsal spinal cord 2 mm rostrally and 2 mm caudally to the injury site at 24 hrs after spinal cord injury. MEASUREMENTS: Rats from each group were examined for neurologic function and contents of brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor, and neurotrophin-3. Survival, migration, and differentiation of human umbilical cord mesenchymal stem cells, regeneration of axons, and formation of glial scar were also explored by using immunohistochemistry and immunofluorescence. MAIN RESULTS: Recovery of hindlimb locomotor function was significantly enhanced in the human umbilical cord mesenchymal stem cells grafted animals at 5 wks after transplantation. This recovery was accompanied by increased length of neurofilament-positive fibers and increased numbers of growth cone-like structures around the lesion site. Transplanted human umbilical cord-mesenchymal stem cells survived, migrated over short distances, and produced large amounts of glial cell line-derived neurotrophic factor and neurotrophin-3 in the host spinal cord. There were fewer reactive astrocytes in both the rostral and caudal stumps of the spinal cord in the human umbilical cord-mesenchymal stem cell group than in the control group. CONCLUSIONS: Treatment with human umbilical cord mesenchymal stem cells can facilitate functional recovery after traumatic spinal cord injury and may prove to be a useful therapeutic strategy to repair the injured spinal cord.

Amelioration of rCBF and PbtO2 following TBI at high altitude by hyperbaric oxygen pre-conditioning.

OBJECTIVES: Hypobaric hypoxia at high altitude can lead to brain damage and pre-conditioning with hyperbaric oxygen (HBO) can reduce ischemic/hypoxic brain injury. This study investigates the effects of high altitude on traumatic brain injury (TBI) and examines the neuroprotection provided by HBO preconditioning against TBI. METHODS: Rats were randomly divided into four groups: HBO pre-conditioning group (HBOP, n=10), high altitude group (HA, n=10), plain control group (PC, n=10) and plain sham operation group (sham, n=10). All groups were subjected to head trauma by weight drop device except for the sham group. Rats from each group were examined for neurological function, regional cerebral blood flow (rCBF) and brain tissue oxygen pressure (PbtO(2)) and were killed for analysis by transmission electron microscope. RESULTS: The score of neurological deficits in the HA group was highest, followed by the HBOP group and the PC group, respectively. Both rCBF and PbtO(2) were the lowest in the HA group. Brain morphology and structure seen via the transmission electron microscope was diminished in the HA group, while fewer pathological injuries occurred in the HBOP and PC groups. CONCLUSIONS: High altitude aggravates TBI significantly and HBO pre-conditioning can attenuate TBI in rats at high altitude by improvement of rCBF and PbtO(2). Pre-treatment with HBO might be beneficial for people traveling to high altitude locations.

[Morphological observation of human keratinocytes tridimensionally cocultured with xenogenic acellular dermal matrix].

OBJECTIVE: To establish the tridimensional culture method for tissue-engineered skin to observe the histomorphological change in human immortal KC strain (HacaT)cocultured with xenogenic acellular dermal matrix (ADM). METHODS: The ADM was prepared from SD rats by a modified method. HaCaTs were cultured in defined KC-serum free medium. HaCaTs in log growth phase were inoculated on ADM at the cell density of 2 x 10(5)/cm(2). They were submergedly cultured for 5 days and then changed to air-liquid phase culture for another 5 days. ADM and growth of HaCaTs on day 1 and 5 after cocultured with ADM were observed with scanning electron microscope. The histological change in ADM and HaCaTs on day 1, 5, and 10 after cocultured with ADM were examined by HE staining. RESULTS: The gross appearance of ADM was white with smooth and soft texture, and intact collagen bundles without cellular residue. HaCaTs adhered and stretched out pseudopodia on the surface of the ADM on day 1 after combined culture, and a monolayer of cells was formed on day 5, growing into 3-6 layers of cells on day 10 with a tendency to grow into ADM. CONCLUSIONS: SD rats ADM is benefit for the adhesion of HaCaTs and the permeation of nutrient solution, from which an engineered multiple-layered human skin can be obtained within 10 days.

In vitro labeling of human umbilical cord mesenchymal stem cells with superparamagnetic iron oxide nanoparticles.

Human umbilical cord mesenchymal stem cells (hUC-MSCs) transplantation has been shown to promote regeneration and neuroprotection in central nervous system (CNS) injuries and neurodegenerative diseases. To develop this approach into a clinical setting it is important to be able to follow the fates of transplanted cells by noninvasive imaging. Neural precursor cells and hematopoietic stem cells can be efficiently labeled by superparamagnetic iron oxide (SPIO) nanoparticle. The purpose of our study was to prospectively evaluate the influence of SPIO on hUC-MSCs and the feasibility of tracking for hUC-MSCs by noninvasive imaging. In vitro studies demonstrated that magnetic resonance imaging (MRI) can efficiently detect low numbers of SPIO-labeled hUC-MSCs and that the intensity of the signal was proportional to the number of labeled cells. After transplantation into focal areas in adult rat spinal cord transplanted SPIO-labeled hUC-MSCs produced a hypointense signal using T2-weighted MRI in rats that persisted for up to 2 weeks. This study demonstrated the feasibility of noninvasive imaging of transplanted hUC-MSCs.

Traditional Chinese herb Dihuang Yinzi (DY) plays neuroprotective and anti-dementia role in rats of ischemic brain injury.

AIM OF THE STUDY: Traditional Chinese herb Dihuang Yinzi (DY) is well known to treat neurological diseases by traditional Chinese medical practitioners. This study is to elucidate its neuroprotective and anti-dementia role in ischemic brain injury. MATERIALS AND METHODS: The effects of DY on the pathohistological changes, lactate dehydrogenase (LDH) release, Morris water maze task, expression of synaptophysin (SYP) and extracellular signal-regulated protein kinase (ERK) of hippocampi of rats with ischemic brain injury were investigated. RESULTS: This study showed that DY not only significantly decreased the number of TUNEL-positive cells but also reduced the LDH release of hippocampus of model rat. Morris water maze test showed that the ability of learning and memory of rats dramatically impaired after ischemic brain injury. However, DY ameliorated the impairment of learning and memory of ischemic rats. Furthermore, western blotting and immunohistochemical data showed that the expression of extracellular regulated protein and synaptophysin, which correlates with synaptic formation and function, decreased after ischemic insult. However, DY inhibited the reduction of ERK an SYP expression in a dose-dependent way. CONCLUSION: These results suggest that DY possesses neuroprotective and anti-dementia properties, at least in part, by preventing the loss of neural cells and synapses in ischemic brain injury.