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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.

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Background and Objective: Hypoxia is one of the most common clinical stresses that occur during pregnancy, which has adverse effects on fetal development. Fish oil, with its antioxidant properties, prevents fetal disorders during pregnancy. This study was conducted to determine the effects of fish oil on apparent congenital abnormalities and fetal dimensions caused by hypoxia during gestation in rats.
Methods: In this experimental study, 36 female pregnant Wistar rats were divided into 6 groups of control, hypoxia, fish oil 0.5 ml, fish oil 1 ml, hypoxia+fish oil 0.5 ml, and hypoxia + fish oil 1 ml. Fish oil was administered by gavage, and the hypoxia model was established between 6 and 15 days of gestation by 3 hours of daily exposure to 10% oxygen and 90% nitrogen. On the 20th day of pregnancy, the embryos were removed from the uterus. First, the number of obtained embryos from each group was counted. Then, in terms of apparent abnormalities, the number of live fetuses and fetal resorption was evaluated. Finally, the length and weight of the fetuses were measured.
Results: The frequency of embryos with apparent abnormalities in the hypoxia and control groups was 18.18% and nil, respectively. The frequency of fetal resorptions in the hypoxia and control groups was 27.27% and 1.92%, respectively. Moreover, fetal weight and length were significantly reduced in the hypoxia group compared with the control group (P<0.05). However, the average weight and length of fetuses in the hypoxia groups receiving fish oil showed a significant increase compared to the hypoxia group (P<0.05).
Conclusion: Hypoxia during pregnancy in rats reduces fetal body dimensions and increases fetal abnormalities. However, fish oil can reduce the harmful effects of hypoxia on apparent congenital abnormalities and fetal body dimensions during pregnancy.