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Objective To detect the expression of TrkA in the brain of the Wistar rats during the embryonic phase.Methods Adult Wistar rats were fed in one cage.It was E0 day when sepermia were found in vaginal suppository and vaginal smear.The expressions of TrkA in the brain of Wistar rats during various brain regions were observed by immunohistochemistry on E13,E15,E17,E19 and E21 day. Results On E13 day no obvious expression of TrkA was observed in the embryonic brain.The expression of TrkA had an obviously increasing tendency in the cortex of telencephalon from E15 day to E17 day.And on E17 day,the positive rate of the expression of TrkA reached the second peak.While on E19 day,the expression of TrkA had a temporary decreasing.Then on E21 day the expression of TrkA reached the highest peak.The striatum and hippocampus developed later than the telencephalon till E17 day,and the expressions of TrkA during these stages were same as the cerebrum.Conclusion From E15 to E17 day,obvious expressions of TrkA are observed in the embryonic telencephalon,and it accords with embryonic induction.
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Objective To explore a kind of simple and high efficient approach to differentiate human embryonic stem cells(hESCs)into neural stem cells(NSCs).Methods hESCs were cultured in bacterial culture dish filled with serum free medium to gain embryoid bodies.Then the mature embryoid bodies grew in the special medium including B27 and noggin by adherent culture to differentiate into NSCs. Results The hESCs kept floating in the bacterial culture dish and growing all the time and then formed mature embryoid bodies 7 to 10 days later.The embryoid bodies could be differentiated into highly pure (96.4%)nestin positive cells.And these cells were differentiated into all kinds of neural cells if cultured further.Conclusions This kind of method is less time-consuming,cheaper,and more efficient than those of the results in literatures reported.It affords very good source of seed cells for cell transplantation therapy in the future.
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Objective To investigate the possibility of commitment differentiation of embryonic stem cells induced by the medium of cultured retinal neurons of SD rats. Methods The medium from cultured retinal neurons of SD rats were collected, sterilized and mixed with DMEM medium according to 2∶3 proportion, ES cells were cultured with these mixed medium and were observed under the phase contrast microscope daily, the induced cells were identified by NF immunohistochemistry methods. Results The ES cells cultured with these mixed medium can differentiate into neuron like structure, and the induced cells were positive in NF immunofluorescence staining. Conclusion The medium from cultured retinal neurons of SD rats can induce ES cells commitment differentiation into neuron like structure.
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Induction is a process in which the developmental pathway of one cell is controlled by signals emitted from another. Mesoderm induction is the first inductive interaction in the Xenopus enbryo and probably occurs in all vertebrates. It is a very important event as it is implicated in the regulation of morphogenesis. Nieuwkoop first demonstrated the importance of vegetal endoderm in inducing the mesoderm. Slack and co-workers incorporated the information obtained from experimental embryology in a "three signal" model for mesoderm induction in amphibians (signals arising from ventral vegetal hemisphere, dorsal vegetal hemisphere and the organizer). More recent research has resulted in the detection of mesoderm inducing factors which are members of FGF and TGF--β families. Activin, a member of the TGF-ß family, has been shown to induce differential gene expression and cell differentiation in a concentrationdependent manner giving credence to the theory of morphogen gradients. Study of mesoderm induction in the chick embryo is much more difficult due to several reasons. Novel experimental approaches, however, have been used which point to the role of activin and FGF in chick mesoderm induction. The demonstration of mesoderm inducing activity of activin and FGF in other groups of vertebrates, particularly the chick embryo brings out the possibility of a universal mechanism of mesoderm induction being operative in all the vertebrates.
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Objective To investigate the protective effect of nerve growth factor (NGF) on apoptosis of cultured human fetal retinal pigment epithelium (HFRPE) cells induced by indomethacin (IN) in vitro. Methods Subcultured HFRPE cells were treated with different concentrations of IN to establish apoptotic model. The protective effect of NGF on apoptosis of cultured HFRPE cells were assessed using an acridine orange (AO) staining method and transmission electron microscopy (TEM). Results HFRPE cells exposed by 200 600 ?mol/L IN for 24 hours elicited typical apoptosis morphological changes, including condensed chromation, nuclear fragmentation and reduction of nuclear size and cell volume. There was a statistically difference in HFRPE cells with apoptosis between 200 ?mol/L IN+500 ?g/L NGF and 200 ?mol/L IN groups ( q=3 9204,P=0.0320) ; there was a significant difference in HFRPE cells with apoptosis in 400 ?mol/L IN+500 ?g/L NGF and 400 ?mol/L IN as well ( q=9 7915,P=0 0001). Conclusion NGF has an protective effect on IN induced HFRPE cells apoptosis.