神经再生素促大鼠海马神经元生长的研究

目的 研究牛膝提取物神经再生素(NRF)对体外培养的大鼠海马神经元生长的促进作用及其对生长相关蛋白-43(GAP-43)表达的影响.方法 以体外原代培养的胎鼠海马神经元为研究模型,通过相差显微镜采用Scion软件测量不同浓度NRF(0.25mg/L、0.5mg/L、1mg/L)、不同作用时间(6h、12h、24h)对海马神经元神经突起生长的影响;通过实时荧光定量PER观察NRF不同浓度(0.25mg/L、0.5mg/L、1.0mg/L)及不同作用时间(6h、12h、24h)对海马神经元GAP-43基因表达的影响;采用免疫荧光细胞化学法和Western blotting,观察不同浓度NRF(0.25mg/L、0.5mg/L、1.0mg/L)加药24h后,对海马神经元GAP-43表达的影响.结果 NRF可有效地促进海马神经元的生长,加药后24h作用浓度为1mg/L时,作用最强;实时荧光定量RT-PCR、免疫荧光细胞化学法和Western blotting的结果提示,NRF能增加体外培养的海马神经元GAP-43的表达,浓度为1.0mg/L时,作用最佳.结论 NRF能促进体外培养的海马神经元神经突起的生长和GAP-43基因的表达,表明NRF对海马神经元具有神经营养作用.     

Peripheral nerve grafts lacking viable Schwann cells fail to support central nervous system axonal regeneration

Summary Peripheral nerve grafts were implanted bilaterally into the diencephalon of adult hamsters. One graft segment contained both viable Schwann cells and their basal lamina tubes. The Schwann cell population in the second graft segment was killed by freezing prior to implantation. Seven weeks after graft implantations, the extracranial end of each graft segment was exposed, transected and labelled with a fluorescent tracer substance. One week after the labelling procedure each animal was perfused and the diencephalon and midbrain were examined. Ultrastructural analyses of both types of graft demonstrated the persistence of the Schwann cell-derived basal lamina tubes. Retrogradely labelled neurons were found in all cases in which an intact graft remained in place for two months, but were seen in only one case with a frozen graft. Large numbers of myelinated and unmyelinated axons were seen within the intact grafts, but no axons were found in the previously frozen grafts. These results indicate that lesioned CNS axons are able to regenerate vigorously when provided with an environment which includes viable Schwann cells. But, CNS axons regenerate less well, if at all, when Schwann cells are absent. Further, it appears that Schwann cell-derived basal lamina tubes, when isolated from their parent cells, are insufficient to initiate or sustain CNS axonal regeneration.This material is based upon work supported by the National Science Foundation under grant BNS-8416911     

A composite poly-hydroxybutyrate-glial growth factor conduit for long nerve gap repairs

There is considerable evidence that peripheral nerves have the potential to regenerate in an appropriate microenvironment. We have developed a novel artificial nerve guide composed of poly 3-hydroxybutyrate (PHB) filled with glial growth factor (GGF) suspended in alginate hydrogel. Gaps of 2-4 cm in rabbit common peroneal nerve were bridged using a PHB conduit containing either GGF in alginate hydrogel (GGF) or alginate alone (Alginate), or with an empty PHB conduit (Empty). Tissues were harvested 21, 42 and 63 days post-operatively. Schwann cell and axonal regeneration were assessed using quantitative immunohistochemistry. At 21 days, addition of GGF increased significantly the distance of axonal and Schwann cells regeneration in comparison with that observed in Alginate and Empty conduits for both gap lengths. The axons bridged the 2-cm GGF conduits gap by 63 days, with a comparable rate of regeneration seen in 4-cm conduits. Schwann cells and axonal regeneration quantity was similar for both gap lengths in each group. However, at all time points the quantity of axonal and Schwann cells regeneration in GGF grafts was significantly greater than in both Alginate and Empty conduits, the latter showing better regeneration than Alginate conduits. The results indicate an inhibitory effect of alginate on regeneration, which is partially reversed by the addition of GGF to the conduits. In conclusion, GGF stimulates a progressive and sustainable regeneration increase in long nerve gap conduits.     

Regeneration and growth of the liver in 3-week-old mice of different strains

At the age of 3 weeks, C57BL mice have comparatively low proliferative activity of their hepatocytes when the liver grows normally, but also during regeneration of the liver 44 h after its extensive resection (mitotic index 16%). Animals of the same age but of other strains (noninbred, CBA, and CC57BR), however, in most cases have a higher mitotic index of their hepatocytes both under normal conditions and during regeneration of the liver (42, 70, and 60%). This pattern of interlinear differences in mitotic activity of the hepatocytes during growth and regeneration of the liver was still found 7 days after the beginning of the experiment. The results indicate genetic determination of the level of proliferative activity of cells.Laboratory of Growth and Development, Institute of Human Morphology, Academy of Medical Sciences of the USSR. (Presented by Academician of the Academy of Medical Sciences of the USSR, A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 4, pp. 475–477, April, 1976.     

施万细胞和一氧化氮合酶抑制剂对大鼠脊髓损伤后背核神经元存活及其轴突再生的影响

目的探讨施万细胞(SCs)和一氧化氮合酶(NOS)抑制剂L-NNA联合应用能否促进脊髓损伤后背核神经元存活及其轴突再生。方法20只成年大鼠分为对照组、SCs组、L-NNA组和SCs L-NNA组。在SCs L-NNA组动物T11脊髓段半横断后在损伤处植入施万细胞，术后腹腔内注射L-NNA。结果脊髓半横断后30d，对照组L1脊髓段损伤侧背核神经元数量减少，其胞体皱缩，NOS表达阳性。SCs组存活的神经元增加的同时其NOS表达增强，胞体也发生皱缩。L-NNA组和SCs L-NNA组存活的神经元也增加，但NOS表达降低，其胞体皱缩得到改善。各组中仅在SCs L-NNA组L1脊髓损伤侧背核观察到有被FG标记的神经元胞体，提示其再生轴突穿越损伤区到达头端脊髓组织。结论SCs和L-NNA都可促进脊髓半横断背核受损伤神经元的存活；两者联合应用能更好地促进受损伤背核神经元存活及其轴突再生。     

Diverse functions of the p75 neurotrophin receptor

The pan-neurotrophin receptor p75NTR belongs to a large family of receptors, which includes tumor necrosis factor receptors, Fas and approximately 25 other members. The p75NTR is the first receptor to be cloned molecularly. Recent years have seen the emergence of a consensus regarding the signaling pathways activated by p75NTR and its potential biological function, although receptor characterization had not been targeted for some years. We now know that p75NTR has surprisingly diverse effects, ranging from cell death to regulation of axon elongation. This diversity can be explained by the complex formation of p75NTR with other receptors and multiple signaling molecules that interact with the intracellular domain of p75NTR.     

Effect of fetal tissue transplantation on reparative processes in experimental liver cirrhosis

Reparative regeneration after fetal tissue transplantation and after surgical stimulation was studied in rats with experimental cirrhosis of the liver. Fetal tissue restored the morphology and function of cirrhotic liver and modified functional activity of peritoneal macrophages. Translated fromByulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 130, No. 8, pp. 216–219, August, 2000     

大鼠肝再生过程中碱性磷酸酶活性变化及其超微细胞化学研究

目的 研究2／3肝切除后大鼠肝再生过程中碱性磷酸酶(AKP)活性的变化及其细胞定位。方法 利用比色法对AKP活性进行定量分析；用酶的原位复性电泳技术分析再生肝中AKP的种类和活性变化；用电镜细胞化学方法研究酶定位。结果 在肝部分切除后的肝再生期间，AKP出现两个活性高峰(16h和19h)，在每个活性高峰后，AKP均有显著下降；获得3种肝型AKP同工酶(140、160和180kD)，其中180kD的AKP只在肝再生过程中出现；随着肝再生的进展，AKP活性出现在细胞的不同部位。结论 AKP在肝再生过程中起重要作用，可能参与细胞代谢、物质转运、DNA合成和细胞分化。     

人工组织神经移植物修复狗缺损坐骨神经后腓肠肌的形态观察

目的 了解复合型医用可降解材料制成的人工组织神经移植物辅加神经再生素修复狗坐骨神经缺损后，腓肠肌的形态变化。方法 将人工组织神经移植物连接在狗的坐骨神经缺损30mm处。以自体神经桥接和神经缺损的狗为对照组Ⅰ和Ⅱ。术后6个月时取腓肠肌进行称重、特殊染色和组织化学染色，显微镜下了解腓肠肌的形态变化并进行图像定量分析，同时了解肌纤维的超微结构变化。结果 术后6个月，实验组腓肠肌的萎缩形态指标变化均轻于对照组Ⅱ，而与对照组Ⅰ相似。结论 经人工组织神经移植物修复缺损的坐骨神经后，使腓肠肌又重新获得神经支配，肌肉萎缩明显减轻。     

Disconnected optic axons persist in the visual pathway during regeneration of the retino-tectal projection in the frog

Summary In this study, we crushed one optic nerve in the frog Litoria (Hyla) moorei and at intervals thereafter anterogradely labelled optic axons with horseradish peroxidase (HRP). For one series, HRP was applied between the eye and the crush site and in a second series between the crush site and the chiasm. A tectal projection of regenerating axons was seen in both series but, in addition, up to 12 weeks post-crush, the second series displayed an additional projection. Its appearance matched that of the disconnected, but persisting, optic axon terminals which are found after enucleation or optic nerve ligation. We conclude that, in the frog, many disconnected optic axons persist throughout the period of optic nerve regeneration and of restoration of an orderly retino-tectal map.Abbreviation HRP horseradish peroxidase