[Retracted] Neuroglobin Is Involved in the Hypoxic Stress Response in the Brain

Figure 3

Changes of neuroglobin positive neuron density at different ages during cortical development. (a) In the neocortex II-IV layers, fitting curve between the neuroglobin positive neuronal density () and age was made; the regression equation was calculated with the following formula: (). The number of Ngb-positive neurons per unit area was the highest at P1, then, the number continuously dropped at P14, and the density fluctuation of the Ngb-positive neurons tends to a stable level. From P1 to P14, the number of Ngb-positive neurons per unit area was remarkably decreased at each time point compared with the previous time point, and the density of Ngb-positive neurons showed no significant difference from P14 to 1 year (, ). (b) In the neocortex V-VI layers, fitting curve between the neuroglobin positive neuronal density () and age was made; the regression equation was calculated with the following formula: (); at layers V-VI, the number of Ngb-positive neurons per unit area gradually climbed from E16 and reached the peak at P1 and then declined, till it leveled off after P14. Compared with E18, the density of neuroglobin positive neurons increased significantly at P1 (, ). The density of the Ngb-positive neurons displayed a downward trend from P1 to P3, and the labeled cells decreased rapidly from P7 to P14 (, ). Four-month-old Kunming mice were randomly assigned to the control group and hypoxic stress group. The intervention group was subjected to weight-loaded swimming exercise, while the control group was fed conventionally without any intervention. (a) Ngb (red) and NeuN (green) immunofluorescence double labeling staining in mouse neocortex in the control group. (b) The expression of Ngb-positive neurons in mouse cortex under the mild hypoxia stress. (c) The density of Ngb-positive neurons at layers II-IV and V-VI in mild hypoxic stress group presented significant increase compared with the blank group (). in both (a) and (b). .

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