The molecular events involved in oligodendrocyte precursor cell proliferation induced by the conditioned medium from b104 neuroblastoma cells.

The conditioned medium from B104 neuroblastoma cells (B104CM) induces proliferation of oligodendrocyte progenitor cells (OPCs) in vitro. However, the molecular events that occur during B104CM-induced proliferation of OPCs has not been well clarified. In the present study, using OPCs immunopanned from embryonic day 14 Sprague-Dawley rat spinal cords, we explored the activation of several signaling pathways and the expression of several important immediate early genes (IEGs) and cyclins in OPCs in response to B104CM. We found that B104CM can induce OPC proliferation through the activation of the extracellular signal-regulated kinases 1 and 2 (Erk1/2), but not PI3K or p38 MAPK signaling pathways in vitro. The IEGs involved in B104CM-induced OPC proliferation include c-fos, c-jun and Id2, but not c-myc, fyn, or p21. The cyclins D1, D2 and E are also involved in B104CM-stimulated proliferation of OPCs. The activation of Erk results in subsequent expression of IEGs (such as c-fos, c-jun and Id-2) and cyclins (including cyclin D1, D2 and E), which play key roles in cell cycle initiation and OPC proliferation. Collectively, these results suggest that the phosphorylation of Erk1/2 is an important molecular event during OPC proliferation induced by B104CM.

PDGF-AA and bFGF mediate B104CM-induced proliferation of oligodendrocyte precursor cells.

The conditioned medium from B104 neuroblastoma cells (B104CM) induces proliferation of οligodendrocyte precursor cells (OPCs) in vitro, which indicates that certain factors contained within B104CM give instructional signals that direct the proliferation of OPCs. However, the OPC-proliferative factors present in B104CM have yet to be identified. Platelet-derived growth factor AA (PDGF-AA), basic fibroblast growth factor (bFGF) and insulin-like growth factor-1 (IGF-1) have been reported to act as potent mitogens for OPC proliferation. This raises the possibility that B104CM induces proliferation of OPCs through secretion of PDGF­AA, bFGF and/or IGF-1. In the present study, we detected the expression and levels of PDGF-AA, bFGF and IGF-1 in B104 cells and B104CM, and observed the expression of their receptors in OPCs. The results indicated that these growth factors were expressed in B104 cells and B104CM. All 3 receptors, PDGFR, FGFR2 and IGF-1R, were also detected in OPCs. Furthermore, B104CM-stimulated OPC proliferation could be markedly decreased by both AG1295 (an inhibitor of PDGFR) and PD173074 (an inhibitor of FGFR). However, the inhibition of IGF-1R with AG1204 did not affect the proliferation of OPCs. Our study suggests that the PDGF-AA and bFGF in B104CM are 2 key factors that stimulate OPC proliferation.

Calcitonin gene-related peptide enhances CREB phosphorylation and attenuates tau protein phosphorylation in rat brain during focal cerebral ischemia/reperfusion.

Calcitonin gene-related peptide (CGRP) is a potent vasodilator and immune cell modulator. Exogenous CGRP could increase the cerebral blood flow significantly and protect the ischemic neurons, but its mechanism is not entirely clear. The effect of CGRP on the expressions of CREB and tau in the ipsilateral parietal cortex were detected in focal cerebral ischemia/reperfusion model. The expression of CREB mRNA decreased in ischemia/reperfusion group (I/R group) compared with that of the sham operation group, and it got highest in CGRP group. CREB expression was lesser in I/R group than sham group, but it became more in CGRP group than I/R group. Phospho-CREB became more in I/R group, and it got most in CGRP group in the cortex. No significant difference was observed on Tau mRNA expression in all the groups. The level of tau hyperphosphorylation at Ser199/202 site and total tau in rat parietal cortex were significantly higher in I/R group than sham group. CGRP significantly inhibited tau hyperphosphorylation and the level of total tau also significantly reduced in CGRP group than that in I/R group. CGRP can upregulate the expression of CREB and phospho-CREB and attenuate the level of tau hyperphosphorylation in the ischemic neurons of the parietal cortex during focal cerebral ischemia/reperfusion. Phosphorylating CREB and inhibiting tau phosphorylation are probably involved in the mechanism of protective effect of CGRP to ischemic neurons.

Cyclic-AMP response element binding protein and tau are involved in the neuroprotective mechanisms of nerve growth factor during focal cerebral ischemia/reperfusion in rats.

Nerve growth factor (NGF) has protective and therapeutic effects after cerebral ischemic injury. However, its mechanism of action is not clear. We explored the protective mechanism of exogenous NGF on rat hippocampal neurons after focal cerebral ischemia/reperfusion. Changes were detected in the expression of cyclic-adenosine monophosphate (AMP) response element binding protein (CREB) messenger ribonucleic acid (mRNA), CREB protein, phosphorylated CREB, tau mRNA, total tau protein and the state of phosphorylation of tau protein at the serine 199/202 site. NGF treatment significantly increased the expression of CREB mRNA, CREB and phosphorylated CREB in the hippocampal CA1 region. NGF alleviated the level of phosphorylation of tau and the expression level of total tau. It is possible that the protective effect of NGF on the ischemic neuron was due to the activation of transcription and translation of CREB, the reduction in the level of phosphorylation of tau protein, and the activation of a series of signal pathways.

Quantitative analysis of the microstructure of human umbilical vein for assessing feasibility as vessel substitute.

We explored the feasibility of human umbilical vein (HUV) as a small-caliber vessel substitute. HUVs of 50 fetuses were collected on spontaneous miscarriage or labor with the pregnant women's permission. Gestational age ranged 24-42 weeks, and parturients were 20-30 years old. Each sample was sliced into 5 mum frozen transverse sections and stained with hematoxylin-eosin (HE), Weigert, aniline blue, and orange yellow G. The geometric morphological indexes and microstructural component were measured by a computer image analysis system. The media thickness was 0.186, 0.203, 0.237, 0.264, and 0.268 mm at 24-27, 28-32, 33-36, 37-40, and 41-42 weeks, respectively (F = 133.35, p < 0.01); diameters were 1.861, 1.962, 2.303, 2.464, and 2.465 mm (F = 37.35, p < 0.01), respectively. The media thickness and diameter of HUVs increased with gestational age. The elastin content of media increased at 24-40 weeks, but the collagen content and collagen/elastin (C/E) ratio decreased. Elastin content in the proximal segment was higher than in the distal segment [10.16, 6.36 Aa%, (Aa% is the unit of relative content, ie, the ratio of absolute areas to the total tested area of smooth muscle, collagen and elastin in the vascular wall) F = 5.77-12.3, p < 0.05], with the collagen to elastin (C/E) ratio increasing from the proximal to the distal segment (F = 7.63-13.4, p < 0.05). Our results suggest that the microstructural component of HUVs (2.0-3.0 mm caliber) at 37-40 weeks of gestation was similar to that of the small-caliber arteries and had moderate amounts of collagen and elastin and good elasticity, i.e., a good C/E ratio; therefore, HUV may be a substitute for small-caliber arteries (e.g., brachial, ulnar, radial, right coronary, anterior tibial, and posterior tibial). HUV is one of several graft materials that may be used when autogenous saphenous vein is absent or inadequate.

Biomechanical properties of ascending aorta and pulmonary trunk in pigs and humans.

BACKGROUND: This study aims to obtain the biomechanical properties of ascending aorta and pulmonary trunk between healthy humans and pigs of different months, so as to provide necessary biomechanical experimental basis for anastomosing blood vessel in pig-to-human heart xenotransplantation. METHODS: Ascending aorta and pulmonary trunks of the six deceased donors (male 4, female 2) and 42 Chinese Hubei white pigs aged 1-7 months were performed biomechanical test. The blood vessel was given periodic permanent loading and unloading, and repeated force-deformation data were obtained. The elastic properties of the blood vessels were obtained by curve from experimental data. RESULTS: The biomechanical material constant of ascending aorta and pulmonary trunk of pigs did not increase with the increase of age (F = 14.569, P = 0.126). The biomechanical material constant of humans was basically similar to that of pigs aged 1-7 months (F = 12.264, P = 0.225). The elastic modulus was the biggest in pigs aged 7 months in comparison with that in other ages (F = 27.425, P = 0.032). There was no significant difference of elastic modulus of corresponding blood vessel between humans and pigs of different months (F = 17.328, P = 0.215). CONCLUSIONS: Our present study suggests that there was no significant difference of elastic properties of ascending aorta and pulmonary trunks between humans and pigs. From biomechanical aspects, anastomosis of corresponding ascending aorta and pulmonary trunks in the process of pig-to-human heart xenotransplantation may be feasible.

[Observation on therapeutic effect of acupuncture at Fengchi (GB 20) at different stages on pseudobulbar palsy].

OBJECTIVE: To observe the therapeutic effect of acupuncture at different stages on pseudobulbar palsy. Methods Two hundred and forty cases of pseudobulbar palsy were divided into 4 groups according to different courses of disease, i.e. group I, the course within 10 days; group II, between 10-30 days; group III, between 1-3 months; group IV, between 3-6 months. They were treated with acupuncture at Fengchi (GB 20) for 2 courses, and then their therapeutic effects were ohserved. RESULTS: The effective rate was 100.0% in the group I, 96.7% in the group II, 83.3% in the group III and 76.7% in the group IV, with a significant difference among the 4 groups (P < 0.01). CONCLUSION: Acupuncture at Fengchi (GB 20) at any stage has therapeutic effect on pseudohulbar paisy, hut the earlier treatments, the better the therapeutic effects.

Nerve-pathways of acupoint Fengch'ih in rat by anterograde transport of HRP.

AIM: To study the nervous-pathways of Fengch'ih acupuncture by means of anterograde transport of aqueous solution of horseradish peroxidase (HRP). METHODS: Fifty Wistar rats were randomly divided into 1, 2, 3, 4, and 5 d groups, and every group had 10 animals. HRP (30% aqueous solution) was injected into a Fengch'ih. Serial, transverse or capital, 40 microm sections of the cervical spinal ganglia, cervical and thoracic spinal cord segment and brain were cut on a cryotome. Sections were incubated for HRP histochemistry according to the tetramethylbenzidine (TMB). Part of the sections were counterstained with neutral red. RESULTS: After 1 d of survival times, many labeled cell bodies were found in 1-4 cervical spinal ganglia, anterior horn of 1-4 cervical spinal cord, ventromedial division of facial nucleus, accessory facial nucleus ipsilaterally. With increasing survival times, the intensity of labeled cells were slightly decreased. CONCLUSION: Fengch'ih may bring into full play its effect by correlation of posterior ear branch of facial nerve and anterior branch of 2-3 cervical nerve with 1-4 cervical the anterior horn of the spinal cord, ventromedial division of facial nucleus, accessory facial nucleus.

Evaluation of murine models of permanent focal cerebral ischemia.

BACKGROUND: To date murine models of permanent focal cerebral ischemia have not been well characterized. The purposes of this paper were to compare three different permanent middle cerebral artery occlusion (MCAo) models with or without craniectomy, and to identify an ideal mouse model of permanent focal cerebral ischemia. METHODS: Experiments were performed on 45 healthy adult male Kunming mice, weighing 28 to 42 g. The animals were randomly assigned to three groups (n = 15 in every group) based on surgical procedure: MCAo via the external carotid artery (ECA), MCAo via the common carotid artery (CCA), and direct ligation of the middle cerebral artery (MCA). Each day post-ischemia, the animals were scored using an eight-grade neurological function scale, and mortality was also recorded. Seven days post-ischemia, the brains were removed for lesion size determination using triphenyltetrazolium chloride staining. Correlation analysis of lesion volume and neurological score was carried out. RESULTS: Mortality in the group receiving direct MCA ligation was lowest among the three groups, and there was a significant difference between the direct MCA ligation group and the two intraluminal occlusion groups (P < 0.05). In all groups, neurological scores gradually increased with prolongation of ischemic duration, peaking after two days, then gradually decreasing. In the direct MCA ligation group, however, neurological scores were relatively stable. There was a significant correlation between infarct volume and neurological score 7 days after MCAo in every group (all r > 0.7, P < 0.05), suggesting good reproducibility of lesion volume in the three groups, but the infarct volume was more constant in the direct MCA ligation group. CONCLUSION: The direct ligation model of MCAo provides an optimal means of studying permanent focal cerebral ischemia, and is preferable to the models using intraluminal sutures.