Pyrroloquinoline quinone attenuates iNOS gene expression in the injured spinal cord

Pyrroloquinoline quinone (PQQ) is a naturally occurring redox cofactor that acts as an essential nutrient, antioxidant, and redox modulator. PQQ has been demonstrated to oxidize the redox modulatory site of N-methyl-d-aspartic acid (NMDA) receptors. Such agents are known to be neuroprotective in experimental stroke models. Therefore, we examined the possible ameliorating effect of PQQ on spinal cord injury (SCI) in adult rats. Intraperitoneal administration of PQQ effectively promoted the functional recovery of SCI rats after hemi-transection, which was preceded by the attenuation of the expression of inducible nitric oxide (NO) synthase (iNOS) mRNA in the injury site. NO is involved in the secondary detrimental mechanisms and has been implicated in NMDA receptor-mediated neurotoxicity. In fact, administration of PQQ induced significantly decreased lesion size and increased axon density adjoining the lesion area. These observations suggest that PQQ protects against the secondary damage by reducing iNOS expression following primary physical injury to the spinal cord.     

Exposure to extremely low-frequency magnetic field restores spinal cord injury-induced tonic pain and its related neurotransmitter concentration in the brain

Spinal cord injury (SCI) is unequivocally reported to produce hyperalgesia to phasic stimuli, while both hyper- and hypoalgesia to tonic stimuli. The former is spinally mediated and the latter centrally. Besides, its management is unsatisfactory. We report the effect of magnetic field (MF; 17.96 μT, 50 Hz) on tonic pain behavior and related neurotransmitters in the brain of complete thoracic (T13) SCI rats at week 8. Adult male Wistar rats were divided into Sham, SCI and SCI+MF groups. Formalin-pain behavior was compared utilizing 5 min block pain rating (PR), 60 min session-PR, time spent in various categories of increasing pain (T0–T3) and flinch incidences. Serotonin (5-HT), dopamine (DA), norepinepherine (NE), gamma-aminobutyric acid (GABA), glutamate and glycine were estimated in brain tissue by liquid chromatography–mass spectrometry. Session-PR, block-PR and number of flinches were significantly lower, while time spent in categories 0–1 was higher in the SCI versus Sham group. These parameters were comparable in the SCI+MF versus Sham group. 5-HT concentration in cortex, remaining forebrain areas and brain stem (BS), was lower while GABA and NE were higher in BS of SCI, which were comparable with Sham in the SCI+MF group. The concentration of DA, glutamate and glycine was comparable amongst the groups. The data indicate significant hypoalgesia in formalin pain while increased in GABA, NE and decreased in 5-HT post-SCI, which were restored in the SCI+MF group. We suggest beneficial effect of chronic (2 h/day × 8 weeks) exposure to MF (50 Hz, 17.96 μT) on tonic pain that is mediated by 5-HT, GABA and NE in complete SCI rats.     

A Bibliometric Study of the Trend in Articles Related to Risk Assessment Published in Science Citation Index

In this study, a bibliometric method was used to evaluate the global scientific production of risk assessment research for the last 16 years and provide insights into the characteristics of the risk assessment research activities and tendencies that may exist in the papers. Data were obtained on the online version of SCI, Web of Science from 1992 to 2007. Two important respects of the paper characteristics were analyzed: (i) performance of publication and (ii) research tendency and hotspots. The main results were as follows: English-language articles took the majority of all the publications. Number of articles in this field increased from 1 in 1968 to 1037 in 2007. Human and Ecological Risk Assessment published the most papers in this field, taking 3% of all. Research tendency was investigated by statistically analyzing the distribution of paper title, author keyword, and keyword plus. Furthermore, a new method named “word cluster analysis” was successfully applied to find the research hotspots of this field. Research hotspots of risk assessment mainly focused on three subject categories: environmental science, ecology, and epidemiology. This new bibliometric method can help relevant researchers realize the panorama of global risk assessment research, and establish the further research direction.     

炎性小体在诱导脊髓损伤神经炎症中的作用

脊髓损伤的治疗与康复一直是医学领域的重大难题,尤其是在改善损伤的神经功能方面进展甚微。继发性损伤是造成脊髓损伤后神经功能障碍的主要原因,炎症反应是继发性损伤阶段最重要的病理过程。急性期通过抑制神经炎症来减轻继发性损伤被认为可减轻神经功能损害而达到神经保护作用。炎性小体是一类蛋白质复合体,由模式识别受体中的NLRs家族和PHYIN家族的受体蛋白质作为主要框架组装并命名,常见的炎性小体包括NLRP1、NLRP3、NLRC4(IPAF)、AIM2等。在感染或受到损伤刺激时,炎性小体在细胞质内组装,并激活促炎症蛋白酶胱天蛋白酶1(caspase-1),活化的胱天蛋白酶1一方面促进促炎症细胞因子IL-1β和IL-18的前体成熟和分泌,另一方面介导细胞焦亡。细胞焦亡以细胞肿胀破裂并释放细胞内容物为特征,是在炎症和应激的病理条件下诱导的程序性细胞死亡方式。促炎症细胞因子和焦亡释放的胞内物质都可作为促炎信号引发炎症反应。近期发现,炎性小体通过诱导促炎因子释放以及介导细胞焦亡等途径, 参与激活脊髓损伤后的炎症级联反应,加重继发性神经炎症。靶向抑制炎性小体的激活可减轻炎症反应,促进神经细胞存活,达到神经保护作用。因此,炎性小体有望成为脊髓损伤治疗的新靶点。本文拟从炎性小体的结构及其在脊髓损伤中的作用、激活机制和治疗前景进行综述,以期为后续研究提供思路。     

Upregulation of anti-apoptotic factors in upper motor neurons after spinal cord injury in adult zebrafish

Unlike mammals, fish motor function can recover within 6–8 weeks after spinal cord injury (SCI). The motor function of zebrafish is regulated by dual control; the upper motor neurons of the brainstem and motor neurons of the spinal cord. In this study, we aimed to investigate the framework behind the regeneration of upper motor neurons in adult zebrafish after SCI. In particular, we investigated the cell survival of axotomized upper motor neurons and its molecular machinery in zebrafish brain. As representative nuclei of upper motor neurons, we retrogradely labeled neurons in the nucleus of medial longitudinal fasciculus (NMLF) and the intermediate reticular formation (IMRF) using a tracer injected into the lesion site of the spinal cord. Four to eight neurons in each thin sections of the area of NMLF and IMRF were successfully traced at least 1–15 days after SCI. TUNEL staining and BrdU labeling assay revealed that there was no apoptosis or cell proliferation in the axotomized neurons of the brainstem at various time points after SCI. In contrast, axotomized neurons labeled with a neurotracer showed increased expression of anti-apoptotic factors, such as Bcl-2 and phospho-Akt (p-Akt), at 1–6 days after SCI. Such a rapid increase of Bcl-2 and p-Akt protein levels after SCI was quantitatively confirmed by western blot analysis. These data strongly indicate that upper motor neurons in the NMLF and IMRF can survive and regrow their axons into the spinal cord through the rapid activation of anti-apoptotic molecules after SCI. The regrowing axons from upper motor neurons reached the lesion site at 10–15 days and then crossed at 4–6 weeks after SCI. These long-distance descending axons from originally axotomized neurons have a major role in restoration of motor function after SCI.     

The impact of Acacia saligna invasion on Italian coastal dune EC habitats

Alien species can represent a threat to several ecosystems because they can alter species relationships and ecosystem function. In Italy, Acacia saligna is a major invader and it forms dense stands in coastal environments. We analyze the impact of A. saligna in Italian Mediterranean dune systems. We randomly sampled coastal dune vegetation and investigated its floristic composition with ordination techniques. We compared species richness in invaded and non-invaded plots with rarefaction curves and analyzed the frequency of focal and ruderal species. A. saligna invaded Mediterranean scrub (habitats 2250* and 2260) and coastal Pinus dune wood (habitat 2270*) and it is particularly prevalent in sunny areas of habitat 2270*. We observed an increase in ruderal species and a decrease in focal species in the invaded plots of habitat 2270*. We suggest that more open and disturbed areas are more prone to A. saligna invasion.     

Controlled Cervical Laceration Injury in Mice

Use of genetically modified mice enhances our understanding of molecular mechanisms underlying several neurological disorders such as a spinal cord injury (SCI). Freehand manual control used to produce a laceration model of SCI creates inconsistent injuries often associated with a crush or contusion component and, therefore, a novel technique was developed. Our model of cervical laceration SCI has resolved inherent difficulties with the freehand method by incorporating 1) cervical vertebral stabilization by vertebral facet fixation, 2) enhanced spinal cord exposure, and 3) creation of a reproducible laceration of the spinal cord using an oscillating blade with an accuracy of ±0.01 mm in depth without associated contusion. Compared to the standard methods of creating a SCI laceration such as freehand use of a scalpel or scissors, our method has produced a consistent lesion. This method is useful for studies on axonal regeneration of corticospinal, rubrospinal, and dorsal ascending tracts.     

生物多样性保护及其相关学科SCI收录期刊介绍

将SCI收录的12种生物多样性保护核心期刊及中国进入科学引文索引和科学引文索引扩展版的10种相关期刊进行了全面的揭示,包括英文刊名、汉译刊名、出版周期、原版刊号、最新影响因子、国际标准刊号、出版地、出版者、联系地址、最新期刊网址,期刊描述等全方位的期刊信息。期刊描述内容包括:期刊的创刊年以及期刊的发展,期刊主要内容及使用的语言,网站可免费获取的该刊目次和文摘及全文信息等。     

Calibrated Forceps Model of Spinal Cord Compression Injury

Compression injuries of the murine spinal cord are valuable animal models for the study of spinal cord injury (SCI) and spinal regenerative therapy. The calibrated forceps model of compression injury is a convenient, low cost, and very reproducible animal model for SCI. We used a pair of modified forceps in accordance with the method published by Plemel et al. (2008) to laterally compress the spinal cord to a distance of 0.35 mm. In this video, we will demonstrate a dorsal laminectomy to expose the spinal cord, followed by compression of the spinal cord with the modified forceps. In the video, we will also address issues related to the care of paraplegic laboratory animals. This injury model produces mice that exhibit impairment in sensation, as well as impaired hindlimb locomotor function. Furthermore, this method of injury produces consistent aberrations in the pathology of the SCI, as determined by immunohistochemical methods. After watching this video, viewers should be able to determine the necessary supplies and methods for producing SCI of various severities in the mouse for studies on SCI and/or treatments designed to mitigate impairment after injury.