Objective To study the effects of repeated hypoxic exposures (HEs) on glycolysis, mitochondrial oxi-dative phosphorylation and energy charge in mouse brain. Methods Adult BALB/c mice were repeatedly exposed to hypoxia for 5 times and the standard tolerant time and body temperature were recorded. The activities of PFK, PK and mitochondrial complex Ⅰ in the brain were assayed. Phosphoadenosines and energy charge were measured. Results Repeated HEs prolonged the hypoxic tolerance and reduced the body temperature. The activities of PFK and PK experienced regular changes, with an increase in 1st and 3rd HEs and a decline to control levels in 5th HE. The complex Ⅰ activity continued to decrease during HEs. The energy charge was stable. Conclusion HEs lead to a regular change of glycolysis, a continued inhibition of mitochondrial oxidative phosphorylation, and a main-tained energy charge in the brains of mouse.

OBJECTIVE: To investigate the protective effect of vitamin D (VD) against hyperoxia-induced bronchopulmonary dysplasia (BPD) in newborn mice and explore the mechanism. METHODS: Thirty-six newborn mice were randomly divided into air + VD group, air + saline group, hyperoxia + VD group, and hyperoxia + saline group. In all the groups, saline or VD was administered on a daily basis intramuscular injection. After 3 weeks of treatment, the mice were weighed and cardiac blood was collected for measurement of serum VD level using ELISA, and histological examination of the lungs was performed. Radial alveolar counting (RAC) and alveolar secondary interval volume density were measured using image analysis software. The expression levels of vascular endothelial cell growth factor (VEGF) and VEGF receptor 2 (VEGFR2) in the lung tissues were detected using Western blotting. RESULTS: The weight gain rate of the mice and the weight of the lungs were significantly higher in air + saline group and air + VD group than in the hyperoxia + saline group. The RAC was significantly lower in hyperoxic+saline group than that in hyperoxia+VD group ( < 0.001), and was significantly higher in hyperoxic+VD (125 times) than in hyperoxia + VD (1250 times) group ( < 0.01). The alveolar secondary protrusion count was significantly higher in hyperoxic+VD (1250 times) group than in hyperoxic+saline group ( < 0.001), and was significantly higher in hyperoxia+VD (125 times) group than in hyperoxia + VD (1250 times) group ( < 0.01). Compared with that in air + saline group, VEGFR2 expression was significantly lowered in hyperoxia+saline group ( < 0.05) and in air+VD group ( < 0.05); VEGFR2 expression was significantly higher in hyperoxia+VD (1250 times) group than in hyperoxia+saline group ( < 0.001) and hyperoxia+VD (125 times) group ( < 0.001); VEGFR2 expression was significantly higher in hyperoxia+VD (125 times) group than in hyperoxia+ saline group ( < 0.05). CONCLUSIONS In newborn mice with BPD, VD supplement can increase the weight of the lungs and promote lung maturation, and a higher concentration of VD can better protect the lungs and promote the growth of pulmonary blood vessels.
Animals ; Animals, Newborn ; Bronchopulmonary Dysplasia ; Hyperoxia ; Lung ; Mice ; Vitamin D