Neuroglobin Facilitates Neuronal Oxygenation through Tropic Migration under Hypoxia or Anemia in Rat:How Does the Brain Breathe?

The discovery of neuroglobin(Ngb),a brain-or neuron-specific member of the hemoglobin family,has revolutionized our understanding of brain oxygen metabolism.Currently,how Ngb plays such a role remains far from clear.Here,we report a novel mechanism by which Ngb might facilitate neuronal oxygenation upon hypoxia or anemia.We found that Ngb was present in,co-localized to,and co-migrated with mitochondria in the cell body and neurites of neurons.Hypoxia induced a sudden and prominent migration of Ngb towards the cytoplasmic membrane(CM)or cell surface in living neurons,and this was accompanied by the mitochondria.In vivo,hypotonic and anemic hypoxia induced a reversible Ngb migration toward the CM in cerebral cortical neurons in rat brains but did not alter the expression level of Ngb or its cytoplasm/mitochondria ratio.Knock-down of Ngb by RNA interference significantly diminished respiratory succinate dehydrogenase(SDH)and ATPase activity in neuronal N2a cells.Over-expression of Ngb enhanced SDH activity in N2a cells upon hypoxia.Mutation of Ngb at its oxygen-binding site(His64)significantly increased SDH activity and reduced ATPase activity in N2a cells.Taken together,Ngb was physically and functionally linked to mitochondria.In response to an insufficient oxygen supply,Ngb migrated towards the source of oxygen to facilitate neuronal oxygenation.This novel mechanism of neuronal respiration provides new insights into the understanding and treatment of neurological diseases such as stroke and Alzheimer’s disease and diseases that cause hypoxia in the brain such as anemia.

Evaluation of the Effects of Standard Rescue Procedure on Severe Trauma Treatment in China

Background：This study aimed to evaluate the effects of standard rescue procedure （SRP） in improving severe trauma treatments in China.Methods：This study was conducted in 12 hospitals located in geographically and industrially different cities in China.A standard procedure on severe trauma rescue was established as a general rule for staff training and patient treatment.A regional network （system） efficiently integrating prehospital rescue,emergency room treatments,and hospital specialist treatments was built under the rule for information sharing and improving severe trauma treatments.Treatment outcomes were compared between before and I year after the implementation of the SRP.Results：The outcomes of a total of 74,615 and 12,051 trauma cases were collected from 12 hospitals before and after the implementation of the SRP.Implementation of the SRP led to efficient cooperation and information sharing of different treatment services.The emergency response time,prehospital transit time,emergency rescue time,consultation call time,and mortality rate of patients were 24.24 ± 4.32 min,45.69 ± 3.89 min,6.38 ± 1.05 min,17.53 ± 0.72 min,and 33.82% ± 3.87% （n =441）,respectively,before the implementation of the standardization and significantly reduced to 10.11 ± 3.21 min,22.39 ± 4.32 min,3.26 ± 0.89 min,3.45 ± 0.45 min,and 20.49% ± 3.11%,separately （n =495,P 〈 0.05） after that.Conclusions：Staff training and SRP can significantly improve the efficiency of severe trauma treatments in China.