外置电场治疗急性脊髓损伤的实验研究

以联合行为记分法（ＣＢＳ）、脊髓诱发电位（ＳＣＥＰ）、及组织形态计量学作为观察指标，观察了外置电场对实验性大鼠急性脊髓损伤模型的疗效，结果显示；接受外置电场治疗的动物的脊髓功能恢复率为９／１０，而对照组只有４／１０，ＣＢＳ法证实两组之间存在着非常显著的差异（Ｐ＜０．０１）；组织形态计量学分析，治疗组与对照组４周时的微囊计数与空腔容积存在着显著性差异（Ｐ＜０．０１Ｐ＜０．０５）；脊髓诱发电位观察，亦证实外置电场治疗组的ＳＣＥＰ潜伏期逐渐恢复正常，而对照组则相对延长（Ｐ＜０．０１）。表明了外置电场有助于大鼠损伤脊髓功能的恢复。     

Effect of Granulocyte Colony-Stimulating-Factor Administration on Tissue Regeneration Due to Thioacetamide-Induced Liver Injury in Rats

It has been shown recently that granulocytecolony-stimulating factor (G-CSF) accelerates andenhances the hepatocyte proliferative capacity ofpartially hepatectomized rats. In the present study, weinvestigated the effect of G-CSF administration in a ratmodel of liver injury and regeneration, induced bythioacetamide (TAA) injection. TAA (300 mg/kg bodyweight) was injected intraperitoneally in male Wistarrats, and this was followed by administration ofeither saline (group A) or G-CSF at a dose of 150g/kg body weight (group B), 24 hr later. The animalswere killed at different time points after TAA treatment and the rate of tritiated thymidineincorporation into hepatic DNA, the activity of theenzyme thymidine kinase (EC 2.7.1.21) in the liver, andthe assessment of the mitotic index of hepatocytes, wereemployed to estimate liver regeneration. Theadministration of TAA caused severe hepatic injury,recognized histopathologically and by the raisedactivities of the serum hepatic enzymes aspartate andalanine aminotransferases. The hepatic injury, which peaked 36 hr afterTAA injection, was followed by a regenerative process ofhepatocytes presenting peaks at time points of 48 and 60hr (group A). The administration of G-CSF 24 hr after the injection of TAA (group B) causeda statistically significantly increase in the hepatocyteproliferation indices examined (P < 0.001), comparedto those found in group A at the same time points. It was concluded that G-CSFadministration enhanced the hepatocyte proliferativecapacity in this model of liver injury induced by TAAadministration.     

猴脊髓损伤的实验研究

猴６只,用Ａｌｅｎ氏法以１５０ＧＣＦ力和２００ＧＣＦ力砸伤脊髓腰１部位。各分成针刺组、给药组及对照组。实验结果提示针刺或ＡＴＰ治疗脊髓损伤未能得到满意的效果,神经纤维未见到再生现象。与对照组之间无明显差别。脊髓损伤的恢复情况从本实验研究的结果分析似与脊髓损伤当时力的大小有直接密切关系。其针刺和给药可能与提高机体抵抗力有一定关系。     

龟板对局灶性脑缺血后神经干细胞的作用

[目的]探讨补肾中药龟板对局灶性脑缺血后神经干细胞的作用。[方法]采用大脑中动脉线栓法造成局灶性脑缺血大鼠模型。应用免疫组织化学技术检测神经上皮干细胞蛋白（Nestin)的表达。[结论]提示补肾中药龟板可减轻神经损伤症状和对局灶性脑缺血后神经干细胞有促进增殖作用。     

促肝细胞生长素对慢性肝损伤鼠肝部分切除术后肝细胞的影响

目的　 研究促肝细胞生长素 (主要成分为肝细胞生长因子 )对慢性肝损伤时肝部分切除术后肝再生和肝功能的影响。 方法　 以四氯化碳和乙醇联合诱导大鼠的慢性肝损伤模型 ,对其行 30 %肝部分切除术 ,术后 10d经腹腔注射促肝细胞生长素 (分对照组、小剂量组、大剂量组 ) ,同时建立正常对照组。观察不同剂量促肝细胞生长素对肝再生、肝功能和肝储备功能的影响。 结果　 小剂量组与对照组的总蛋白、白蛋白、谷丙转氨酶 (AST )、谷草转氨酶 (ALT)、总胆固醇、动脉血酮体比比较 ,差异无显著性 ( P >0 .0 5 )。大剂量组与对照组的AST ,ALT ,总胆固醇、动脉血酮体比的比较差异显著 ( P <0 .0 1)。电镜和光镜观察显示 ,大剂量的促肝细胞生长素能促进肝再生。 结论　 应用大剂量促肝细胞生长素可明显改善肝功能和肝储备功能 ,促进肝细胞再生     

Bioinformatics and microarray analysis of microRNA expression profiles of murine embryonic stem cells,neural stem cells induced from ESCs and isolated from E8·5 mouse neural tube

Abstract

To better understand whether microRNAs (miRNAs) are involved in the self-renewal of stem cells and fate determination of neural stem cells and to identify the miRNA expression patterns of different neural stem cells (NSC) in vitro and in vivo, we examined miRNA expression profiles of murine embryonic stem cells (ESC), NSC induced from ESC and isolated from E8·5 mouse neural tube (E8·5-NSC) using microarray technique. It was found that a total of 40 miRNAs had similar expression level in all the three cells [false discovery rate (FDR)=0, fold change <3·0]. Moreover, q-PCR showed that some members of miR-106b and miR-17–92 families were expressed in the ESC, NSC induced from ESC (ESC-NSC) and hematopoietic stem cells (HSC). Bioinformatical analysis showed that 'stemness genes' (p21/CDKN1A, p57/CDKN1C and PTEN) were putative targets of miR-106b and miR-17–92 families. A total of 95 miRNAs were found to experience significant change (FDR=0, fold change >5·0) when the ESC differentiated into NSC. On the basis of miRNA, mRNA expression variance and predicted target genes of miRNA, we formulated a bioinformatical model for miRNA control of ESC-NSC differentiation. Then, the miRNA expression pattern was compared between NSC obtained in vitro and in vivo, and it was found that only 8% of miRNAs were different between the two NSCs. This study suggested that miR-106b and miR-17–92 families may promote the renewal of stem cells by targeting PTEN, p21/CDKN1A and p57/CDKN1C. Some miRNAs may play a key role in gene re-programming during ESC-NSC differentiation, and a substantial homogeneity exists between NSCs derived in vitro and those in vivo.     

Inhibition of AF116909 gene expression enhances the differentiation of neural stem cells

Abstract

Objectives: Neural stem cells (NSCs) are self-renewed, pluripotent cells that can differentiate into neurons, astrocytes and oligodendrocytes. Such multipotency that allows production of specific types of nerve cells for basic research and therapeutic purposes depends on how these cells are directed in their differentiation. Here, we investigate the function of the AF116909 gene in the differentiation of NSC.

Methods: NSC culture was isolated from the striatum corpora of embryonic brain tissues in a 14-day pregnant rat. A constructed RNAi (RNA-mediated interference) vector was transfected to knock down the expression of this gene. Afterwards, RT–PCT was applied to examine the presence of endogenous AF116909 mRNA and the effect of RNA interference.

Results: After the knockdown of this gene, we detected that the differentiation rate of cells was enhanced to 80% on the 11th day in comparison with 12% in the control cells transfected with the expression vector alone.

Discussion: These findings suggest that AF116909 functions in inhibiting the differentiation of NSCs, and AF116909 gene-targeting by RNAi provides a useful method to study the differentiation mechanisms of NSCs.     

Lateralities of motor control and the alien hand always coincide: further observations on directionality in callosal traffic underpinning handedness

Abstract

Although the relationship of handedness to the ability to talk has been known to the ancients (Psalm 137, for example) the exact knowledge of anatomical underpinnings of this relationship at the public level is a new understanding. This article pursues another corollary of the anatomy sustaining laterality of motor control, i.e. the variability of the alien/unruly hand in patients who have suffered injury to the largest tract connecting the two hemispheres, i.e. the corpus callosum. It is shown that the lateralities of the command center (major hemisphere) and that of the alien hand always coincide, despite the apparent variability of the affected hand in such events (i.e. right hand of left hand in different right handed patients). According to the newly discovered circuitry, the hard-wired directionality in callosal traffic (neural handedness) determines the laterality of the alien/unruly hand after callosal injury, rather than the avowed handedness of the subject (behavioral handedness). The discrepancy between neural and behavioral handedness is explained clinically and physiologically. The latter provides for a non-invasive and inexpensive determination of neural handedness of the subject, i.e. the simple reaction time of two symmetrically located effectors in the body. The side with the longer reaction time is seated below the major hemisphere.     

Inhibition of MAPK ERK impairs axonal regeneration without an effect on neuronal loss after nerve injury

Abstract

Activation of extracellular signal-regulated protein kinase (ERK), a member of the mitogen-activated protein kinase family, has been shown to mediate neurite outgrowth-promoting effects of various neurotrophic factors in vitro. Moreover, in vivo, ERK is activated in the primary sensory neurons and associated glial cells after nerve injury. However, the precise role of ERK in nerve regeneration remains unclear.

Objective: This work was aimed to investigate the effects of ERK inhibition on axonal regeneration and neuronal loss after axotomy.

Methods: Unilateral sciatic nerve crush was performed, and inhibition of ERK was achieved by intraperitoneal injection of 300 μg kg^?1 day^?1 of u0126 for 2 weeks in the inhibitor group. For the control group, only the vehicle was given with the same schedule.

Results: ERK was activated in the crushed sciatic nerve, and this was significantly reduced by the inhibitor. In contrast, there was no activation of ERK in the L4/L5 spinal ganglia. Morphological analysis revealed the similar extent of neuronal loss in the two groups. In addition, the mean regeneration distance in the inhibitor group was lower than that of the control group.

Conclusion: These results suggest the crucial role of ERK in nerve regeneration but not sensory neuronal loss after trauma.     

Effects of human neural stem cell transplantation in canine spinal cord hemisection

Abstract

Objectives: Previous works have reported that the transplantation of neural stem cells (NSCs) may improve functional recovery after spinal cord injury (SCI), but these results have been mainly obtained in rat models. In the present work, the authors sought to determine whether the transplantation of human NSCs improves functional outcome in a canine SCI model and whether transplanted NSCs survive and differentiate.

Methods: Human NSCs (HB1. F3 clone) were used in this work. Lateral hemisection at the L2 level was performed in dogs and either (1) Matrigel (200 μl) alone as a growth-promoting matrix or (2) Matrigel seeded with human NSCs (10⁷ cells/200 μl) were transplanted into hemisected gaps. Using a canine hind limb locomotor scale, functional outcomes were assessed over 12 weeks. Immunofluorescence staining was performed to examine cell survival, differentiation and axonal regeneration.

Results: Compared with dogs treated with Matrigel alone, dogs treated with Matrigel + human NSCs showed significantly better functional recovery (10.3 ± 0.7 versus 15.6 ± 0.7, respectively, at 12 weeks; p<0.05). Human nuclei-positive cells were found mainly near hemisected areas in dogs treated with Matrigel + NSCs. In addition, colocalization of human nuclei and neuronal nuclei or myelin basic protein was clearly observed. Moreover, the Matrigel + NSC group showed more ascending sensory axon regeneration.

Conclusions: The transplantation of human NSCs has beneficial effects on functional recovery after SCI, and these NSCs were found to differentiate into mature neurons and/or oligodendrocytes. These results provide baseline data for future clinical applications.