Long Course Hyperbaric Oxygen Stimulates Neurogenesis and Attenuates Inflammation after Ischemic Stroke

Ying-Sheng Lee,Kuo-Chi Niu,Chung-Ching Chio,Ching-Ping Chang,Liang-Chao Wang,Po-Min Chiang,Kuen-Jer Tsai

doi:10.1155/2013/512978

Abstract

Several studies have provided evidence with regard to the neuroprotection benefits of hyperbaric oxygen (HBO) therapy in cases of stroke, and HBO also promotes bone marrow stem cells (BMSCs) proliferation and mobilization. This study investigates the influence of HBO therapy on the migration of BMSCs, neurogenesis, gliosis, and inflammation after stroke. Rats that sustained transient middle cerebral artery occlusion (MCAO) were treated with HBO three weeks or two days. The results were examined using a behavior test (modified neurological severity score, mNSS) and immunostaining to evaluate the effects of HBO therapy on migration of BMSCs, neurogenesis, and gliosis, and expression of neurotrophic factors was also evaluated. There was a lower mNSS score in the three-week HBO group when compared with the two-day HBO group. Mobilization of BMSCs to an ischemic area was more improved in long course HBO treatments, suggesting the duration of therapy is crucial for promoting the homing of BMSCs to ischemic brain by HBO therapies. HBO also can stimulate expression of trophic factors and improve neurogenesis and gliosis. These effects may help in neuronal repair after ischemic stroke, and increasing the course of HBO therapy might enhance therapeutic effects on ischemic stroke.

Highlights

Ischemic stroke is characterized by the interruption of blood flow and oxygen to brain tissues [1]
After middle cerebral artery occlusion (MCAO) insult or Sham procedure, the rats were subjected to hyperbaric oxygen (HBO) therapy or the normal oxygen condition according to group destination
The declining curve of modified neurological severity score (mNSS) in the HBO3wks group became more obvious after day 14 (P < 0.01) (Figure 2(a))

Summary

Introduction

Ischemic stroke is characterized by the interruption of blood flow and oxygen to brain tissues [1]. Stroke remains an important cause of death and disability for humans and stroke therapy remains an important health issue today. Hyperbaric oxygen (HBO) has been used as a primary or adjunctive stroke therapy over years. Mechanism of the neuroprotection of HBO treatment after ischemia was thought to be mediated by improving oxygen supply [3]. HBO treatment can decrease infarction volume on MRI examination and improve neurological outcome [4]. Researchers have demonstrated that exposure to HBO will cause rapid mobilization of bone marrow stem cells in humans, and the number of bone marrow stem cells (BMSCs) remains elevated in peripheral blood during the course of HBO treatments [6]

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Discussion

Conclusion