Neuronal differentiation of PC12 cells induced by sciatic nerve and optic nerve conditioned medium / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Previous work has shown that optic nerve and sciatic nerve conditional medium had neurotrophic activity on neurons. In order to find if the optic nerve conditioned media (CM) had a similar activity to make PC12 cells differentiate as sciatic nerve CM did, we explored the neurotrophic activity in optic nerve CM in the same in vitro system and compared the neurotrophin expression levels in optic and sciatic nerves under both conditions.</p><p><b>METHODS</b>PC12 cells were used to examine the effects of neurotrophins secreted by the sciatic nerve and optic nerve. RT-PCR and real-time QPCR showed that the sciatic nerve and optic nerve produced a range of neurotrophins including nerve growth factor (NGF), brain derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3).</p><p><b>RESULTS</b>The effects of sciatic nerve and optic nerve CM on neurite outgrowth were tested against a range of neurotrophins, and they had different neuritogenic activities. Only NGF and sciatic nerve CM had obvious neuritogenic activities, although the concentration of NGF in the sciatic nerve CM was very low.</p><p><b>CONCLUSIONS</b>Our experiment showed that sciatic nerve CM had a higher neurotrophic activity on PC12 cells than optic nerve CM. These results suggested that peripheral nervous system (PNS) and central nervous system (CNS) had different expression levels of neurotrophin, which may in part explain the lack of ability to regenerate the CNS.</p>

Study on the adoption of Schwann cell phenotype by bone marrow stromal cells in vitro and in vivo / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To explore the possibilities of bone marrow stromal cells (MSCs) to adopt Schwann cell phenotype in vitro and in vivo in SD rats.</p><p><b>METHODS</b>MSCs were obtained from tibia and femur bone marrow and cultured in culture flasks. Beta-mercaptoethanol followed by retinoic acid, forskolin, basic-FGF, PDGF and heregulin were added to induce differentiation of MSCs'. Schwann cell markers, p75, S-100 and GFAP were used to discriminate induced properties of MSCs' by immunofluorescent staining. PKH-67-labelled MSCs were transplanted into the mechanically injured rat sciatic nerve, and laser confocal microscopy was performed to localize the PKH67 labelled MSCs in the injured sciatic nerve two weeks after the operation. Fluorescence PKH67 attenuation rule was evaluated by flow cytometry in vitro.</p><p><b>RESULTS</b>MSCs changed morphologically into cells resembling primary cultured Schwann cells after their induction in vitro. In vivo, a large number of MSCs were cumulated within the layer of epineurium around the injured nerve and expressed Schwann cell markers, p75, S-100, and GFAP.</p><p><b>CONCLUSION</b>MSCs are able to support nerve fiber regeneration and re-myelination by taking on Schwann cell function, and can be potentially used as possible substitutable cells for artificial nerve conduits to promote nerve regeneration.</p>

Chitin biological tube bridging the peripheral nerve with a small gap / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the possibility of bridging small peripheral nerve gap using a de-acetyl chitosan conduit.</p><p><b>METHODS</b>The sciatic nerves of right sides were cut at SD rats. They were divided into 5 Groups randomly; Group A: epineurium suture in situ (n = 24); Group B: biological conduit with a small gap for bridging the peripheral nerve (n = 24, with 5 mm gap); Group C: epineurium suture with distal stump rotated 180 degrees (n = 24); Group D: bridging the nerve by biological conduits with a small gap, but the distal stump rotated 180 degrees (n = 24, with 5 mm gap); Group E: biological conduit with a small gap for bridging the peripheral nerve with NGF (n = 24). Electrophysiological examination, histological examination and myelinated axon counting were applied after 2, 4, 6, 8 weeks after operation respectively.</p><p><b>RESULTS</b>Regenerated nerve fibers were seen in the distal nerve segments of all 5 groups; The nerve conduction velocity of small gap group (group B, D) was faster than that of corresponding simple epineurium suture group (group A, C) at all 2, 4, 6, 8 week time point (P < 0.05). The myelinated axon counting of small gap group (group B, D) was faster than that of corresponding simple epineurium suture group (group A, C) at all 4, 6, 8 week time point (P < 0.01), and there was no statistically significant difference at 2 week time point.</p><p><b>CONCLUSION</b>The repair effects of chitin conduit bridging peripheral nerve with small gap (5 mm) are better than that of epineurium suture directly, and possess the potential to substitute the epineurium suture.</p>

Role of glutamine on preservation of small intestine / 肠外与肠内营养

Objectives: To investigate the effect of the addition of glutamine to WMO solution on the small bowel preservation. Methods:According to preservation solutions, the rats were divided randomly into three groups: University of Wisconsin solution(UW group), WMO solution (WMO group) and WMO solution with the addition of glutamine(WMO G group). And each group was redivided into two subgroups in terms of preservation time of 8 h or 12 h. The intestine was perfused by intubation via abdomial aorta, then the gut was flushed with metronidazole solution(4℃,5%). The proliferation of small intestine was observed through tissue culture. The histology, immunohistochemistry (TUNEL, PCNA) of intestinal mucosa and determination of ATP were used to evaluate the results. Results: Compared with UW group and WMO group, ATP contents of WMO G group were significantly higher, particularly in 12 h subgroup. Apoptosis in WMO G group was slighter than those in UW group and in WMO group. The difference in the two latter was not obviously, although pathological change in UW group was slighter than that in WMO group. The number of positive PCNA cells in WMO G group was more than that in other groups. Conclusions: The addition of glutamine to WMO solution could decrease injury of small bowel induced by cold ischemia, provide energy for the small bowel,and promote the proliferation of small bowel mocosal cell.

The role of glutamine in immunologic cell / 肠外与肠内营养

Glutamine is a conditional essential amino acid. It has many biological functions. It can promote the proliferation of immunologic cell. The common factor is the NADPH which is produced during the metabolism of glutamine.