Pregnancy following spinal cord injury.

Each year about 2,000 women of childbearing age in the United States have a spinal cord injury. Only a few mostly anecdotal reports describe pregnancy after such an injury. In a retrospective study of 16 women with a spinal cord injury, half of whom have a complete injury and about half quadriplegia, 25 pregnancies occurred, with 21 carried to full term. The women delayed pregnancy an average of 6.5 years after their injury, with an average age at first pregnancy of 26.8 years. Cesarean section was necessary in 4 patients because of inadequate progress of labor. In 5 deliveries an episiotomy and local anesthesia were required, 7 required epidural anesthesia, including all cesarean sections, and 10 did not require anesthesia. Several complications have been identified in the antepartum, intrapartum, and postpartum periods including autonomic hyperreflexia, premature labor, pressure sores, urinary tract infections, abnormal presentation, and failure to progress. Ultrasonography and amniocentesis were used selectively. Women with spinal cord injuries can have healthy children, although there are significant risks and these women have special needs.     

Cathepsin B mRNA and protein expression following contusion spinal cord injury in rats

We provide the first data that cathepsin B (Cath B), a lysosomal cysteine protease, is up-regulated following contusion-spinal cord injury (SCI). Following T12 laminectomy and moderate contusion, Cath B mRNA and protein expression profiles were examined from 2 to 168 h post-injury in rats using real-time PCR and immunoblots, respectively. Contusion injury significantly increased [mRNA]Cath B in the injury site and adjacent segments over sham injury levels. While the largest [mRNA]Cath B induction (20-fold over naive) was seen in the injury site, the caudal segment routinely yielded [mRNA]Cath B levels greater than 10-fold over naive. Interestingly, sham injury animals also experienced mRNA induction at several time points at the injury site and in segments rostral and caudal to the injury site. Contusion injury also significantly elevated levels of Cath B proenzyme protein (37 kDa) over sham injury in the injury site (48, 72 and 168 h post-injury). Furthermore, significant protein increases of single and double chain Cath B (both active forms) occurred at the injury site at 72 and 168 h post-injury. Similar significant increases in Cath B protein levels were seen in areas adjacent to the injury site. The induction of Cath B mRNA and protein expression following contusion injury is previously undescribed and suggests that Cath B may potentially be involved in the secondary injury cascade, perhaps for as long as 1 week post-injury.     

Differential gene expression in the EphA4 knockout spinal cord and analysis of the inflammatory response following spinal cord injury

Mice lacking the axon guidance molecule EphA4 have been shown to exhibit extensive axonal regeneration and functional recovery following spinal cord injury. To assess mechanisms by which EphA4 may modify the response to neural injury a microarray was performed on spinal cord tissue from mice with spinal cord injury and sham injured controls. RNA was purified from spinal cords of adult EphA4 knockout and wild-type mice four days following lumbar spinal cord hemisection or laminectomy only and was hybridised to Affymetrix All-Exon Array 1.0 GeneChips?. While subsequent analyses indicated that several pathways were altered in EphA4 knockout mice, of particular interest was the attenuated expression of a number of inflammatory genes, including Arginase 1, expression of which was lower in injured EphA4 knockout compared to wild-type mice. Immunohistological analyses of different cellular components of the immune response were then performed in injured EphA4 knockout and wildtype spinal cords. While numbers of infiltrating CD3+ T cells were low in the hemisection model, a robust CD11b+ macrophage/microglial response was observed post-injury. There was no difference in the overall number or spread of macrophages/activated microglia in injured EphA4 knockout compared to wild-type spinal cords at 2, 4 or 14 days post-injury, however a lower proportion of Arginase-1 immunoreactive macrophages/activated microglia was observed in EphA4 knockout spinal cords at 4 days post-injury. Subtle alterations in the neuroinflammatory response in injured EphA4 knockout spinal cords may contribute to the regeneration and recovery observed in these mice following injury.     

Glial and axonal regeneration following spinal cord injury

Spinal cord injury (SCI) has been regarded clinically as an irreversible damage caused by tissue contusion due to a blunt external force. Past research had focused on the analysis of the pathogenesis of secondary injury that extends from the injury epicenter to the periphery, as well as tissue damage and neural cell death associated with secondary injury. Recent studies, however, have proven that neural stem (progenitor) cells are also present in the brain and spinal cord of adult mammals including humans. Analyses using spinal cord injury models have also demonstrated active dynamics of cells expressing several stem cell markers, and methods aiming at functional reconstruction by promoting the potential self-regeneration capacity of the spinal cord are being explored. Furthermore, reconstruction of the neural circuit requires not only replenishment or regeneration of neural cells but also regeneration of axons. Analysis of the tissue microenvironment after spinal cord injury and research aiming to remove axonal regeneration inhibitors have also made progress. SCI is one of the simplest central nervous injuries, but its pathogenesis is associated with diverse factors, and further studies are required to elucidate these complex interactions in order to achieve spinal cord regeneration and functional reconstruction.     

Glial and axonal regeneration following spinal cord injury

Spinal cord injury (SCI) has been regarded clinically as an irreversible damage caused by tissue contusion due to a blunt external force. Past research had focused on the analysis of the pathogenesis of secondary injury that extends from the injury epicenter to the periphery, as well as tissue damage and neural cell death associated with secondary injury. Recent studies, however, have proven that neural stem (progenitor) cells are also present in the brain and spinal cord of adult mammals including humans. Analyses using spinal cord injury models have also demonstrated active dynamics of cells expressing several stem cell markers, and methods aiming at functional reconstruction by promoting the potential self-regeneration capacity of the spinal cord are being explored. Furthermore, reconstruction of the neural circuit requires not only replenishment or regeneration of neural cells but also regeneration of axons. Analysis of the tissue microenvironment after spinal cord injury and research aiming to remove axonal regeneration inhibitors have also made progress. SCI is one of the simplest central nervous injuries, but its pathogenesis is associated with diverse factors, and further studies are required to elucidate these complex interactions in order to achieve spinal cord regeneration and functional reconstruction.Key words: glia, regeneration, spinal cord, injury, axon     

缺血预处理对兔脊髓缺血再灌注损伤水通道蛋白-4表达的影响

目的探讨缺血预处理（IPC）对兔脊髓缺血再灌注损伤后水通道蛋白-4（AQP-4）表达的影响。方法日本大耳白兔72只,随机分为3组：假手术组（S组）、脊髓缺血再灌注损伤组（I／R组）和缺血预处理组（IPC组）。I／R组和IPC组阻断腹主动脉30min造成脊髓缺血再灌注损伤,IPC组在损伤前短暂阻断腹主动脉5min二次实施预处理,S组暴露肾动脉下腹主动脉但不阻断。分别于再灌注损伤后4h和24h进行神经功能评分,并取L4—6脊髓缺血节段,计算脊髓组织含水量,免疫组化法测定脊髓组织中AQP-4表达水平。结果与S组比较,I／R组神经运动功能评分降低,脊髓组织含水量增加,AQP-4表达增加（P〈0．05）。与I／R组比较,IPC组神经运动功能评分增高,脊髓组织含水量降低,AQP-4表达减少（P〈0．05）。结论IPC可抑制脊髓损伤后AQP-4的表达,进而减轻脊髓水肿,保护缺血再灌注损伤的脊髓。     

Regulation of cholinergic expression in cultured spinal cord neurons

Factors regulating development of cholinergic spinal neurons were examined in cultures of dissociated embryonic rat spinal cord. Levels of choline acetyltransferase (CAT) activity in freshly dissociated cells decreased rapidly, remained low for the first week in culture, and then increased. The decrease in enzyme activity was partially prevented by increased cell density or by treatment with spinal cord membranes. CAT activity was also stimulated by treatment with MANS, a molecule solubilized from spinal cord membranes. The effects of MANS were greatest in low-density cultures and in freshly plated cells, suggesting that the molecule may substitute for the effects of elevated density and cell-cell contact. CAT activity in ventral (motor neuron-enriched) spinal cord cultures was similarly regulated by elevated density or treatment with MANS, whereas enzyme activity was largely unchanged in mediodorsal (autonomic neuron-enriched) cultures under these conditions. These observations suggest that development of cholinergic motor neurons and autonomic neurons are not regulated by the same factors. Treatment of ventral spinal cord cultures with MANS did not increase the number of cholinergic neurons detected by immunocytochemistry with a monoclonal CAT antibody, suggesting that MANS did not increase motor neuron survival but rather stimulated levels of CAT activity per neuron. These observations indicate that development of motor neurons can be regulated by cell-cell contact and that the MANS factor may mediate the stimulatory effects of cell-cell contact on cholinergic expression.     

Increased expression of spinal cord Fos protein induced by bladder stimulation after spinal cord injury

These studies examined Fos protein expression in spinal cord neurons synaptically activated by stimulation of bladder afferent pathways after spinal cord injury (SCI). In urethan-anesthetized Wistar rats after SCI for 6 wk, intravesical saline distension significantly (P 相似文献   

Effects of magnesium sulphate following spinal cord injury in rats

Neutrophil infiltration has been implicated in the secondary destructive pathomechanisms after initial mechanical injury to the spinal cord. Tissue myeloperoxidase (MPO) activity has been shown to be an exclusive indicator of the extent of post-traumatic neutrophil infiltration. We have studied the effect of magnesium sulphate on MPO activity after spinal cord injury in rats. Rats were randomly allocated into 5 groups. Group 1 was control and normal spinal cord samples were obtained after clinical examination. Forty g-cm contusion injury was introduced to Group 2. Group 3 was vehicle, 1 ml of physiological saline was injected post-trauma. Group 4 was given 30 mg/kg methylprednisolone sodium succinate (MPSS) immediately after trauma. Group 5 was given 600 mg/kg magnesium sulphate immediately after trauma. Animals were examined by inclined plane technique of Rivlin and Tator 24 h after trauma. Spinal cord samples obtained following clinical evaluations. Magnesium sulphate treatment improved early functional scores and decreased MPO activity. These findings revealed that magnesium sulphate treatment possesses neuroprotection on early clinical results and on neutrophil infiltration after acute contusion injury to the rat spinal cord.     

Regulation of clusterin expression in mammary epithelial cells

Mammary epithelial cells undergo changes in growth, invasion, differentiation, and dedifferentiation throughout much of adult hood, and most strikingly during pregnancy, lactation, and involution. Clusterin is a multifunctional glycoprotein that is involved in the differentiation and morphogenesis of epithelia, and that is important in the regulation of postnatal mammary gland development. However, the mechanisms that regulate clusterin expression are still poorly understood. Here, we show that clusterin is up-regulated twice during mouse mammary gland development, a first time at the end of pregnancy and a second time at the beginning of the involution. These points of clusterin up-regulation coincide with the dramatic phenotypic and functional changes occurring in the mammary gland. Using cell culture conditions that resemble the regulatory microenvironment in vivo, we determined that the factors responsible for the first up-regulation of clusterin levels can include the extracellular matrix component, laminin, and the lactogenic hormones, prolactin and hydrocortisone. On the other hand, the second and most dramatic up-regulation of clusterin can be due to the potent induction by TGF-beta1, and this up-regulation by TGF-beta1 is dependent on beta1 integrin ligand-binding activity. Moreover, the level of expression of beta-casein, a marker of mammary epithelial cell differentiation, was decreased upon treatment of cells with clusterin siRNA. Overall, these findings reveal several novel pathways for the regulation of clusterin expression during mammary gland development, and suggest that clusterin is a morphogenic factor that plays a key role during differentiation.     

Cellular-scale transport in deformed skeletal muscle following spinal cord injury

Deep tissue injury (DTI) is a severe pressure ulcer initiating in weight-bearing skeletal muscles. Being common in spinal cord injury (SCI) patients, DTI is associated with mechanical cell damage and ischaemia. Muscle microanatomy in SCI patients is characterised by reduced myofibre sizes and smaller, fewer capillaries. We hypothesise that these changes influence mass transport in SCI muscles, making DTI more probable. Using multiphysics models of microscopic cross-sections through normal and SCI muscles, we studied effects of the following factors on transport of glucose and myoglobin (potential biomarker for early DTI detection): (i) abnormal SCI muscle microanatomy, (ii) large tissue deformations and (iii) ischaemia. We found that the build-up of concentrations of glucose and myoglobin is slower for SCI muscles, which could be explained by the pathological SCI microanatomy. These findings overall suggest that microanatomical changes in muscles post-SCI play an important role in the vulnerability of the SCI patients to DTI.     

Activation of Rho in the injured axons following spinal cord injury

Axons of the adult central nervous system have very limited ability to regenerate after injury. This inability may be, at least partly, attributable to myelin-derived proteins, such as myelin-associated glycoprotein, Nogo and oligodendrocyte myelin glycoprotein. Recent evidence suggests that these proteins inhibit neurite outgrowth by activation of Rho through the neurotrophin receptor p75^NTR/Nogo receptor complex. Despite rapidly growing knowledge on these signals at the molecular level, it remained to be determined whether Rho is activated after injury to the central nervous system. To assess this question, we establish a new method to visualize endogenous Rho activity in situ. After treatment of cerebellar granular neurons with the Nogo peptide in vitro, Rho is spatially activated and colocalizes with p75^NTR. Following spinal cord injury in vivo, massive activation of Rho is observed in the injured neurites. Spatial regulation of Rho activity may be necessary for axonal regulation by the inhibitory cues.     

Increased expression of CDK11p58 and cyclin D3 following spinal cord injury in rats

Protein kinases are critical signalling molecules for normal cell growth and development. CDK11^p58 is a p34^cdc2-related protein kinase, and plays an important role in normal cell cycle progression. However its distribution and function in the central nervous system (CNS) lesion remain unclear. In this study, we mainly investigated the protein expression and cellular localization of CDK11 during spinal cord injury (SCI). Western blot analysis revealed that CDK11^p58 was not detected in normal spinal cord. It gradually increased, reached a peak at 3 day after SCI, and then decreased. The protein expression of CDK11^p58 was further analyzed by immunohistochemistry. The variable immunostaining patterns of CDK11^p58 were visualized at different periods of injury. Double immunofluorescence staining showed that CDK11 was co-expressed with NeuN, CNPase and GFAP. Co-localization of CDK11/active caspase-3 and CDK11/proliferating cell nuclear antigen (PCNA) were detected in some cells. Cyclin D3, which was associated with CDK11^p58 and could enhance kinase activity, was detected in the normal and injured spinal cord. The cyclin D3 protein underwent a similar pattern with CDK11^p58 during SCI. Double immunofluorescence staining indicated that CDK11 co-expressed with cyclin D3 in neurons and glial cells. Coimmunoprecipitation further showed that CDK11^p58 and cyclin D3 interacted with each other in the damaged spinal cord. Thus, it is likely CDK11^p58 and cyclin D3 could interact with each other after acute SCI. Another partner of CDK11^p58 was β-1,4-galactosyltransferase 1 (β-1,4-GT 1). The co-localization of CDK11/β-1,4-GT 1 in the damaged spinal cord was revealed by immunofluorescence analysis. The cyclin D3-CDK4 complexes were also present by coimmunoprecipitation analysis. Taken together, these data suggested that both CDK11 and cyclin D3 may play important roles in spinal cord pathophysiology. The authors Yuhong Ji and Feng Xiao contributed equally to this work.     

Respiratory responses to ventilatory loading following low cervical spinal cord injury

This study compared the respiratory responses to ventilatory loading in 8 normal subjects and 11 quadriplegic patients with low cervical spinal cord transection. Progressive hypercapnia was produced by rebreathing. Rebreathing trials were carried out with no added load and with inspiratory resistive loads of 5 and 16 cmH2O. l-1 X s. Measurements were made of ventilation and of diaphragmatic electromyographic activity. Base-line hypercapnic ventilatory responses were significantly lower than normal in the quadriplegic patients, but the effects of resistive loading on the ventilatory responses were comparable in the two groups. The change in peak moving-average diaphragmatic electrical activity (DI peak) for a given change in CO2 partial pressure (PCO2) and DI peak at PCO2 55 Torr increased significantly with resistive loading both in the normal subjects and the quadriplegic patients. In the normal subjects, but not in the quadriplegic patients, inspiratory duration increased progressively with increasing resistance. The increase in DI peak during ventilatory loading in the normal subjects was a consequence of inspiratory prolongation. In contrast, in the quadriplegic patients during breathing against the larger resistive load, there was a significant increase in the average rate of rise (DI peak divided by the time from onset to peak) of diaphragmatic activity. The change in DI rate of rise for a given change in PCO2 increased to 137 +/- 13% (SE), and the DI rate of rise at PCO2 55 Torr increased to 128 +/- 8% (SE) of control values. These results indicate that compensatory increases in diaphragmatic activation during ventilatory loading occur in quadriplegic patients in whom afferent feedback from rib cage receptors is disrupted.     

Altered levels of PGF in cat spinal cord tissue following traumatic injury

Previous studies by others indicated that PGs were present in brain, spinal cord, and c.s.f. of several mammalian species. In the present study we compared levels of PGE and PGF by R.I.A. in spinal cord tissue from traumatized cats and cats pretreated with indomethacin prior to trauma to those of baseline and sham operated controls in order to assess for the first time, to our knowledge, whether meaningful changes in levels of PGE and PGF could be detected which might shed new light on the etiology of spinal cord trauma.Levels of PGF (nanograms/gram wet wt) in the cord segment immediately adjacent to the point of trauma were 8.05 ± 1.50, and 13.13 ± 1.38 for baseline and sham operated cats respectively. Spinal trauma led to more than a 100% increase in PGF levels to 29.26 ± 3.58. Although pretreatment with indomethacin 30 min prior to trauma gave the expected blockade of the PGF response to trauma, a measurable level of PGF (2.55 ± 0.17) was found in the cord after indomethacin. Cord levels of PGF declined after 3 hr in both sham operated and traumatized animals. PGF was maximally stimulated by trauma during the first 3 hr with little effect at 72 hr. Although carefully examined, PGE levels in cat spinal cord appeared to be virtually unaffected by trauma.These findings clearly demonstrate for the first time that traumatic injury to the spinal cord is accompanied by marked increases in PG levels at the site of trauma, and that the observed elevation in PGF in response to trauma can be blocked by indomethacin $\text{in vivo}$. Whether PGF changes are causally related to the etiology of spinal cord trauma, or merely represent a manifestation of PG release as a result of non-specific tissue injury, remains to be seen.     

Spatiotemporal pattern of TRAF3 expression after rat spinal cord injury

TNF receptor associated factor 3 (TRAF3), a member of the TRAF family of intracellular signaling proteins, can directly influence the phosphorylation status and activation of c-Jun N-terminal kinase, participating in CD40-induced apoptosis in carcinoma. However, its expression profile and function are still unclear in spinal cord injury (SCI). In this study, we performed an acute spinal cord contusion injury model in adult rats and detected the dynamic change patterns of TRAF3 expression in spinal cord. Western blot and immunohistochemistry revealed a striking upregulation of TRAF3 after SCI. Double immunofluorescence staining prompted that TRAF3 immunoreactivity was found in neurons rather than astrocytes. Moreover, co-localization of TRAF3/active caspase-3 was detected in neuronal nuclei. To further investigate the function of TRAF3, a neuronal cell line PC12 was employed to establish an apoptosis model in vitro. We analyzed the association of TRAF3 with active caspase-3 on PC12 cells by western blot and immunofluorescent labeling, which was parallel with the data in vivo. Additionally, knocking TRAF3 down with siRNA demonstrated the probable pro-apoptotic role of TRAF3 in the process of neuronal apoptosis. To summarize, we firstly uncover the temporal and spatial expression changes of TRAF3 in SCI. Our data suggest that TRAF3 might be implicated in central nervous system pathophysiology after SCI.     

丝氨酸/苏氨酸蛋白激酶31(STK31)基因在小鼠脊髓损伤后的差异表达

目的:研究丝氨酸/苏氨酸蛋白激酶31(STK31)基因与脊髓损伤修复的潜在关联。方法:以半定量RT-PCR方法检测STK31在小鼠脊髓损伤后的差异表达。结果:STK31在脊髓、肾脏、胃、心脏、大脑、脾、胸腺、肺等器官中均有表达且在脊髓中表达明显;在脊髓损伤后4 h及1 d,STK31表达量显著低于对照组(P<0.01)。结论:STK31基因与脊髓损伤及修复有着潜在的关联。