RESUMO
AIM: To investigate the process of human bone marrow stromal cells (hBMSCs) differentiation into neural-like cells and to determine the role of 26S proteasome in neuronal differentiation. METHODS: Purified hBMSCs were treated with β-mercaptoethanol (β-ME) for 1 day and retinoic acid (RA) for 3 days, followed by growth factor (10 μg/L bFGF or 20 μg/L NGF) for another 3 days. Immunofluorescence was performed to detect the expression of nestin (a neural precursor cells marker), Tuj1 (a premature neuronal marker), and neurofilament (NF, a mature neuronal marker) at all stages of induced differentiation. Immunostaining and RT-PCR were used to analyze the expression of 26S proteasome during neuronal differentiation of hBMSCs. To further confirm the role of 26S proteasome in hBMSCs differentiation, cells were treated with β-ME/RA and then followed by protesome inhibitor MG132 and growth factor. Immunostaining was performed to detect NF-positive cells. RESULTS: Quantification results showed that the untreated cells were almost never positive for nestin, Tuj1 and NF. After treated with β-ME/RA, the numbers of nestin-positive cells (34.41%±1.27%) and Tuj1-positive cells (27.79%±1.27%) were increased. Notably, the numbers of NF-positive cells were significantly increased to 56.72%±2.4% after induction with β-ME/RA/GF. Immunofluorescence analysis showed that undifferentiated hBMSCs cells were weakly stained by antibody against 26S proteasome, but the numbers of cells with high-intensity of 26S proteasome were increased after treated with β-ME/RA. The RT-PCR result of 26S proteasome further confirmed that the mRNA level of the cells differentiated by β-ME/RA (1.33), as well as by β-ME/RA/GF (1.77), was significantly increased compared to the undifferentiated cells. Moreover, hBMSCs incubated with protesome inhibitor MG132 significantly decreased the numbers of NF-positive cells (37.59%±1.52%). CONCLUSION: After induction with β-ME/RA/GF, hBMSCs can be differentiated into neural-like cells, which is concomitant with the increase in 26S proteasome expression. Inhibitor of 26S protesome prevents hBMSCs differentiation, suggesting that 26S proteasome may be involved in the differentiation of hBMSCs into neural-like cells.
RESUMO
Objective To observe how exogenous estrogen influences the distribution and the expression of NOS positive neurons in the supraoptic nuclei of hypothalamus in the overiectomized female rats. Methods The 2-3-month-old female rats(n=40) were selected as the healthy and nulli-copulatory experimental animals. Rats were divided into following groups: normal control group(n=10), ovariectomized control group(n=10), and two experimental groups that have been injected with estrogen for post-operative 40 days(n=10) and for post-operative 70 days(n=10). Finally, all the animals were infused and the brains were removed. Immunohistochemical (SABC) method was adopted to count the number of NOS poitive neurons and observed the NOS poitive neuronal morphology under the light microscope. The image analysis system was used to test the average gray value of immunoreactivity in NOS positive neurons. Results In the ovariectomized control group, the density of NOS positive neurons in supraoptic nucleus was significantly increased and their shapes were bigger than that of the normal control group(P<0.05). The density and the form of the NOS positive neurons in supraoptic nucleons had no apparent difference between the estrogen for post-operative 40 days group and the ovariectomizeed control group(P>0.05).In the group after estrogen-injection 2 months compared with the normal control group, and the ovariectomized control group, both of the NOS positive neurons' density and the size become significantly decreased, and the staining of cells was lesser in the group injected with estrogen for post-operation 70 days. Conclusion The present results suggest that exogenous estrogen may influence the distribution and the expression of NOS positive neurons in supraoptic nucleus of hypothalamus of ovariectomized female rats.