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Background and Objective: Neural stem cells can difrentiate to mature neural cells. Neural stem cells can migrate and repair the damage neural tissue. This study was done to determine the effect of hydro-ethanolic extract of Chamaemelum nobile on cell prolifration and apoptosis of rat hipocample neural stem cells in the oxitative stress condition. Methods: In this experimental study, neural stem cells were isolated from hippocampus of neonatal rat brain. Isolated neural stem cells were treated at 200, 400, 600, 800 and 1000 µg/ml of hydro-ethanolic extract of Chamaemelum nobile for 48h. Cells proliferation rate were evaluated by MTT assay. Anti-apoptotic property of hydro-ethanolic extract of Chamaemelum nobile evaluated using TUNEL assay method. Results: Proliferation of neural stem cells were significantly increased in Chamaemelum nobile extract group in comparision with control (P<0.05). The rate of apoptotic cells were significantly reduced in Chamaemelum nobile extract group compared to control (P<0.05). Conclusion: The hydrethanolic extract of Chamaemelum nobile increases proliferation rate and reduces apoptosis of neural stem cells in the oxitative stress condition.

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Background and Objective: Some problems such as low viability and apoptosis after injection to the body because of exposure to toxic factors such as hypoxia, thermal stress, oxidative stress and food deprivation are encountered with stem cell application. It is suggested that preconditioning of the cells with cytotoxic factors before injection could enhance their efficiency. This study was done to determine the mesenchymal stem cell proliferation exposed to hypoxia by cobalt chloride. Methods: In this experimental study, Mesenchymal stem cells were isolated from rat bone marrow and cultured at least for four times. The cells were cultured in 96 well plates and treated with different concentration (0, 5, 10, 20, 50, 70, 90, 100, 120, 150 and 200 µM) of cobalt chloride for 6, 12, 24 and 46 hours. Cell proliferation was detected by MTT assay [3-(4,5-Dimethylthiazol-2-Yl)-2,5-Diphenyltetrazolium Bromide]. Results: The cells isolated from bone marrow were propagated easily in culture condition. The cells morphology was not altered after exposure to cobalt chloride. Preconditioning of mesenchymal stem cells with 120 µM for 6 hours, 20µM for 12 and 24 hours and 5µM for 48 hours significantly improved cell proliferation after hypoxia in cell culture (P<0.05). Conclusion: Hypoxia preconditioning increases proliferation of mesenchymal stem cell.