Rapid differentiation of human umbilical cord-derived mesenchymal stem cells into insulin-secreting cells under the sole induction of biological products / 生理学报

In order to explore the feasibility of inducing the human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) to differentiate into insulin-secreting cells with biological products alone, hUC-MSCs were separated and purified from the whole umbilical cord by the sequent digestion of collagenase II and trypsin followed by two-step centrifugation. hUC-MSCs were induced with IMDM culture medium containing epidermal growth factor (EGF), basic fibroblast growth factor (bFGF) and Ginkgo biloba extract (GBE). Before and after the induction, the morphological changes were observed under inverse microscope; the islet-related genes were detected by RT-PCR; islet-like clusters (ILCs) were identified by dithizone (DTZ) staining; PDX-1 and immunoreactive insulin (IRI) were examined by immunofluorescence method; the quantity and quality of IRI secretion were assayed by chemiluminescence immunoassay and Western blot respectively. The results showed that the purified hUC-MSCs presented long spindle-like shape and parallel or spiral arrangement which are typical morphological features of MSCs. After the induction, hUC-MSCs changed gradually into round or oval shape and gathered together to form ILCs; there were more than one hundred clusters on the growth surface of a flask of T25; ILCs were stained into positive mauve by DTZ and positive for PDX-1 and IRI; Western blot displayed that most of the IRI was proinsulin (PI). Therefore, hUC-MSCs can rapidly differentiate into insulin-secreting cells under the sole induction of EGF, bFGF, GBE and IMDM, but ILCs are not mature enough to produce sufficient true insulin.

Proliferative capacity of mesenchymal stem cells from human fetal bone marrow and their ability to differentiate into the derivative cell types of three embryonic germ layers / 生理学报

Strong proliferative capacity and the ability to differentiate into the derivative cell types of three embryonic germ layers are the two important characteristics of embryonic stem cells. To study whether the mesenchymal stem cells from human fetal bone marrow (hfBM-MSCs) possess these embryonic stem cell-like biological characteristics, hfBM-MSCs were isolated from bone barrows and further purified according to the different adherence of different kinds of cells to the wall of culture flask. The cell cycle of hfBM-MSCs and MSC-specific surface markers such as CD29, CD44, etc were identified using flow cytometry. The expressions of human telomerase reverse transcriptase (hTERT), the embryonic stem cell-specific antigens, such as Oct4 and SSEA-4 were detected with immunocytochemistry at the protein level and were also tested by RT-PCR at the mRNA level. Then, hfBM-MSCs were induced to differentiate toward neuron cells, adipose cells, and islet B cells under certain conditions. It was found that 92.3% passage-4 hfBM-MSCs and 96.1% passage-5 hfBM-MSCs were at G(0)/G(1) phase respectively. hfBM-MSCs expressed CD44, CD106 and adhesion molecule CD29, but not antigens of hematopoietic cells CD34 and CD45, and almost not antigens related to graft-versus-host disease (GVHD), such as HLA-DR, CD40 and CD80. hfBM-MSCs expressed the embryonic stem cell-specific antigens such as Oct4, SSEA-4, and also hTERT. Exposure of these cells to various inductive agents resulted in morphological changes towards neuron-like cells, adipose-like cells, and islet B-like cells and they were tested to be positive for related characteristic markers. These results suggest that there are plenty of MSCs in human fetal bone marrow, and hfBM-MSCs possess the embryonic stem cell-like biological characteristics, moreover, they have a lower immunogenic nature. Thus, hfBM-MSCs provide an ideal source for tissue engineering and cellular therapeutics.

Effects of fimbria/fornix transection on rat's synaptic configuration of hippocampus CA3 area / 中国应用生理学杂志

<p><b>AIM</b>To observe the effect of fimbria-fornix (FF) transection on rat's hippocampal synaptic configuration.</p><p><b>METHODS</b>Animal models were produced by transecting rat's bilateral fimbria-fornix (FF). Y-type maze test were carried out respectively before and after the models were built, and emphasis was laid on the quantitative analyses of the parameters of synapses in the hippocampal CA3 areas.</p><p><b>RESULTS</b>The thickness of postsynaptic density material, the curvature of synaptic interface and the occurrence of perforated synapses decreased, while the width of synaptic cleft increased.</p><p><b>CONCLUSION</b>Fimbria-fornix transection resulted in evident changes of the synaptic configuration in the hippocampal CA3 areas and we presume that the normal Ach level in the hippocampus plays a key role in maintaining the normal synaptic interface ultrastructure of the hippocampus CA3 area.</p>