EGb761 improves histological and functional recovery in rats with acute spinal cord contusion injury.

STUDY DESIGN: This is an experimental study. OBJECTIVES: The objective of this study was to evaluate the neuroprotective effects of Ginkgo biloba extract 761 (EGb761) on histological features of injured sites and on functional performance of rats subjected to standardized spinal cord injury (SCI). SETTING: This study was conducted in Xian, Shaanxi, China. METHODS: Thirty female Sprague-Dawley rats were randomly divided into three groups: sham-operated, saline-treated control and EGb761-treated. The Basso, Beattie, Bresnahan Locomotor Rating Score (BBB score) was calculated and footprint analysis was performed to evaluate the functional performance of the rats in each group. Hematoxylin and eosin (HE) staining and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and caspase-3 staining were performed to evaluate the necrosis area and apoptotic cells at the injured site in each group. RESULTS: At 14, but not 1, 3 and 7, days post injury (DPI), rats in the EGb761-treated group exhibited significantly better BBB scores compared with the saline-treated control group (P<0.05). The EGb761-treated group also showed increased stride length, decreased stride width and reduced toe dragging at 14 DPI (P<0.05). Analysis of HE staining revealed that the EGb761-treated group had reduced necrosis at the injury site compared with the saline-treated control group (P<0.05). Analysis of TUNEL and caspase-3 staining demonstrated that cell apoptosis was increased at 1-14 DPI, peaking at 24-h post injury in the gray matter, and 7 DPI in the white matter. At 7 DPI, the quantity of apoptotic cells was significantly decreased in the EGb761-treated group. CONCLUSION: EGb761 administration during the acute phase after SCI significantly reduced secondary injury-induced tissue necrosis and cell apoptosis and improved functional performance in rats.

High-dose ascorbic acid administration improves functional recovery in rats with spinal cord contusion injury.

OBJECTIVES: To evaluate the effects of different doses of ascorbic acid (AA) on the functional performance of rats subjected to standardized spinal cord injury (SCI). METHODS: Thirty female Sprague-Dawley rats were divided into three groups (10 animals in each group): control group: rats were subjected to SCI injury and received intraperitoneal saline administration; normal-dose AA group: rats were subjected to SCI injury and received daily intraperitoneal administration of AA at 100 mg kg(-1) bodyweight; high-dose AA group: rats were subjected to SCI injury and received daily intraperitoneal administration of AA at 200 mg kg(-1) bodyweight. The Basso, Beattie, Bresnahan Locomotor Rating Score (BBB score) and footprint analysis were performed to evaluate the functional performance of the rats in each group, and hematoxylin and eosin staining was performed to evaluate necrosis at the injury site. RESULTS: At days 14 and 28 after SCI, rats in the high-dose AA group, but not the normal-dose AA group, exhibited significantly better BBB score compared with the control group (P<0.05). Compared with the control and normal-dose AA group, the high-dose AA group also showed increased stride length, decreased stride width and reduced toe dragging (P<0.05). Histological analysis revealed that both the normal- and high-dose AA groups had reduced necrosis in the injury site compared with the control group (P<0.05). CONCLUSION: High-dose AA administration during the acute phase post SCI significantly reduced secondary injury-induced tissue necrosis and improved functional performance in rats.

Streaming potential of human lumbar anulus fibrosus is anisotropic and affected by disc degeneration.

The streaming potential responses of non-degenerate and degenerate human anulus fibrosus were measured in a one-dimensional permeation configuration under static and dynamic loading conditions. The goal of this study was to investigate the influence of the changes in tissue structure and composition on the electrokinetic behavior of intervertebral disc tissues. It was found that the static streaming potential of the anulus fibrosus depended on the degenerative grade of the discs (p = 0.0001) and on the specimen orientation in which the fluid flows (p = 0.0001). For a statically applied pressure of 0.07 MPa, the ratio of streaming potential to applied pressure ranged from 5.3 to 6.9 mV/MPa and was largest for Grade I tissue with axial orientation and lowest for Grade III tissue with circumferential orientation. The dynamic streaming potential responses of anulus fibrosus were sensitive to the degeneration of the disc: the total harmonic distortion factor increased by 108%, from 3.92 +/- 0.66% (mean +/- SD) for Grade I specimens to 8.15 +/- 3.05% for Grades II and III specimens. The alteration of streaming potential reflects the changes in tissue composition and structure with degeneration. To our knowledge, this is the first reported data for the streaming potential of human intervertebral disc tissues. Knowledge of the streaming potential response of the intervertebral disc provides an understanding of potentially important signal transduction mechanisms in the disc and of the etiology of intervertebral disc degeneration.

The anisotropic hydraulic permeability of human lumbar anulus fibrosus. Influence of age, degeneration, direction, and water content.

STUDY DESIGN: Experimental investigation to determine the effect of intervertebral disc degeneration on the kinetic behavior of fluid in human anulus fibrosus. OBJECTIVES: To measure the hydraulic permeability coefficient of anulus fibrosus specimens in the axial, circumferential, and radial directions to determine the anisotropic permeability behavior of nondegenerate and degenerate human intervertebral discs over a range of ages. SUMMARY OF BACKGROUND DATA: Fluid, a major component of normal intervertebral discs, plays a significant role in their load-supporting mechanisms. Transport of fluid through the intervertebral disc is important for cell nutrition and disc viscoelastic and swelling behaviors. The hydraulic permeability coefficient is the most important material property governing the rate of fluid transport. However, little is known about the anisotropic behavior of this kinetic property and how it is influenced by disc degeneration. METHODS: Using a permeation testing apparatus developed recently, testing was performed on 306 axial, circumferential, and radial anulus fibrosus specimens from the posterolateral region of 30 human lumbar (L2-L3) discs. A new method, flow-controlled testing protocol, was developed to measure the hydraulic permeability coefficient. RESULTS: The hydraulic permeability coefficient of anulus fibrosus depended significantly on the disc degenerative grade (P = 0.0001) and flow direction (P = 0.0001). For the nondegenerate group (Grade I), the hydraulic permeability was significantly anisotropic (P < 0.05), with the greatest value in the radial direction (1.924 x 10(-15) m4/Ns) and the lowest value in the circumferential direction (1.147 x 10(-15) m4/Ns). This anisotropic kinetic (flow) behavior of anulus fibrosus varied with disc degeneration. For the Grade III specimen group, there was no significant difference in hydraulic permeability coefficient among the three major directions (P = 0.37). With disc degeneration, the hydraulic permeability coefficient was decreased in the radial direction and increased in the axial and circumferential directions. The variations of hydraulic permeability coefficient from nondegenerate discs (Grade I) to mildly degenerate discs (Grade II) in each direction were significant (P < 0.05). However, the changes in permeability from Grade II to Grade III groups were not significant (P > 0.05) except in the circumferential direction (3.8% increase; P < 0.05). CONCLUSIONS: The hydraulic permeability of human nondegenerate anulus fibrosus is direction-dependent (i.e., anisotropic), with the greatest permeability in the radial direction. With disc degeneration, the radial permeability of anulus fibrosus decreases, mainly because of decreased water content, and the axial and circumferential permeability coefficients increase, mainly because of structural change, leading to more isotropic permeability behavior for Grade III discs.

Targeting role of glioma stem cells for glioblastoma multiforme.

Glioblastoma multiforme (GBM) is known to be the most common and lethal malignant primary brain tumor. Despite vigorous basic and clinical studies over the past decades, the prognosis of patients with GBM has remained dismal. The fundamental problem with these malignancies occurs due to tumor cells' highly infiltrative nature, precluding a complete surgical resection, and a productive or acquired resistance to cytotoxic therapy. Recent studies demonstrated that GBMs exhibited remarkable cellular heterogeneity and hierarchy containing self-renewing glioma stem cells (GSCs). The malignant growth of GBM can be propagated and sustained by GSCs that are endowed with highly efficient clonogenic and tumor initiation capacities. GSCs can be identified with technical support and are responsible for the invasive potential and recurrence of GBMs. They share core signaling pathways with normal neural stem cells, but also display critical distinctions that provide important clues for useful therapeutic targets. Therefore, targeting GSCs becomes priorities for the development of novel therapeutic paradigms. Herein, we reviewed the existing and promising targeting therapies for GSCs which could effectively inhibit the tumor invasion, proliferation and recurrence of GBMs. Significant features of GSCs, such as invasive growth pattern, angiogenic potential, resistance to traditional therapy and differentiation, are important therapeutic targets. More promising strategies should target GSCs themselves by taking advantages of highthroughput technologies and dissecting the intrinsic molecular nature of GSCs. Novel chemical medicines targeting these GSCs may represent one of the most important directions. Hopefully, this could shed a light on the path we are going to.