Hyperbaric oxygen preconditioning induces tolerance against oxidative injury and oxygen-glucose deprivation by up-regulating heat shock protein 32 in rat spinal neurons.
OBJECTIVE
Hyperbaric oxygen (HBO) preconditioning (HBO-PC) has been testified to have protective effects on spinal cord injury (SCI). However, the mechanisms remain enigmatic. The present study aimed to explore the effects of HBO-PC on primary rat spinal neurons against oxidative injury and oxygen-glucose deprivation (OGD) and the relationship with heat shock proteins (HSPs).


METHODS
Primary rat spinal neurons after 7 days of culture were used in this study. HSPs were detected in rat spinal neurons following a single exposure to HBO at different time points by Western blot. Using lactate dehydrogenase release assay and cell counting kit-8 assay, the injuries induced by hydrogen peroxide (H2O2) insult or OGD were determined and compared among neurons treated with HBO-PC with or without HSP inhibitors.


RESULTS
The results of Western blot showed that HSP27, HSP70 and HSP90 have a slight but not significant increase in primary neurons following HBO exposure. However, HSP32 expression significantly increased and reached highest at 12 h following HBO exposure. HBO-PC significantly increased the cell viability and decreased the medium lactate dehydrogenase content in cultures treated with H2O2 or OGD. Pretreatment with zinc protoporphyrin IX, a specific inhibitor of HSP32, significantly blocked the protective effects of HBO-PC.


CONCLUSIONS
These results suggest that HBO-PC could protect rat spinal neurons in vitro against oxidative injury and OGD mostly by up-regulating of HSP32 expression.
Department of Diving and Hyperbaric Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, People's Republic of China.
Guoyang
G
Huang
Department of Diving and Hyperbaric Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, People's Republic of China.
Jiajun
J
Xu
Department of Diving and Hyperbaric Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, People's Republic of China.
Li
L
Xu
Naval Medical Institute, Shanghai, People's Republic of China.
Shifeng
S
Wang
Department of Diving and Hyperbaric Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, People's Republic of China.
Runping
R
Li
Department of Diving and Hyperbaric Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, People's Republic of China.
Kan
K
Liu
Department of Diving and Hyperbaric Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, People's Republic of China.
Juan
J
Zheng
Department of Diving and Hyperbaric Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, People's Republic of China.
Zhiyu
Z
Cai
Department of Diving and Hyperbaric Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, People's Republic of China.
Kun
K
Zhang
Department of Diving and Hyperbaric Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, People's Republic of China.
Yuandeng
Y
Luo
Department of Diving and Hyperbaric Medicine, Faculty of Naval Medicine, Second Military Medical University, Shanghai, People's Republic of China.
Weigang
W
Xu
D000818:Animals; D002478:Cells, Cultured; D005947:Glucose / Q000172:deficiency*; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D006931:Hyperbaric Oxygenation; D000860:Hypoxia / Q000473:pathology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D010100:Oxygen / Q000494:pharmacology*; D051381:Rats; D013119:Spinal Cord Injuries / Q000378:metabolism / Q000473:pathology; D013131:Spine / Q000187:drug effects / Q000473:pathology*; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects*
D006419:Heme Oxygenase (Decyclizing); C491523:Hmox1 protein, rat; D005947:Glucose; D010100:Oxygen