Oxygen glucose deprivation post-conditioning protects cortical neurons against oxygen-glucose deprivation injury: role of HSP70 and inhibition of apoptosis.
In the present study, we examined the effect of oxygen glucose deprivation (OGD) post-conditioning (PostC) on neural cell apoptosis in OGD-PostC model and the protective effect on primary cortical neurons against OGD injury in vitro. Four-h OGD was induced by OGD by using a specialized and humidified chamber. To initiate OGD, culture medium was replaced with de-oxygenated and glucose-free extracellular solution-Locke's medium. After OGD treatment for 4 h, cells were then allowed to recover for 6 h or 20 h. Then lactate dehydrogenase (LDH) release assay, Western blotting and flow cytometry were used to detect cell death, protein levels and apoptotic cells, respectively. For the PostC treatment, three cycles of 15-min OGD, followed by 15 min normal cultivation, were applied immediately after injurious 4-h OGD. Cells were then allowed to recover for 6 h or 20 h, and cell death was assessed by LDH release assay. Apoptotic cells were flow cytometrically evaluated after 4-h OGD, followed by re-oxygenation for 20 h (O4/R20). In addition, Western blotting was used to examine the expression of heat-shock protein 70 (HSP70), Bcl-2 and Bax. The ratio of Bcl-2 expression was (0.44±0.08)% and (0.76±0.10)%, and that of Bax expression was (0.51±0.05)% and (0.39±0.04)%, and that of HSP70 was (0.42±0.031)% and (0.72±0.045)% respectively in OGD group and PostC group. After O4/R6, the rate of neuron death in PostC group and OGD groups was (28.96±3.03)% and (37.02±4.47)%, respectively. Therefore, the PostC treatment could up-regulate the expression of HSP70 and Bcl-2, but down-regulate Bax expression. As compared with OGD group, OGD-induced neuron death and apoptosis were significantly decreased in PostC group (P<0.05). These findings suggest that PostC inhibited OGD-induced neuron death. This neuro-protective effect is likely achieved by anti-apoptotic mechanisms and is associated with over-expression of HSP70.
Department of Neurology, Henan Provincial People's Hospital, Zhengzhou, 450003, China. sjnk2011@163.com.
Jian-Hua
JH
Zhao
Department of Pharmacy, Henan Provincial People's Hospital, Zhengzhou, 450003, China.
Xian-Li
XL
Meng
Department of Neurology, Henan Provincial People's Hospital, Zhengzhou, 450003, China.
Jian
J
Zhang
Department of Radiology, Henan Provincial People's Hospital, Zhengzhou, 450003, China.
Yong-Li
YL
Li
Department of Neurology, Henan Provincial People's Hospital, Zhengzhou, 450003, China.
Yue-Juan
YJ
Li
Department of Neurology, Henan Provincial People's Hospital, Zhengzhou, 450003, China.
Zhe-Ming
ZM
Fan
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D015687:Cell Hypoxia; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000098:blood supply / Q000166:cytology / Q000196:embryology; D005434:Flow Cytometry; D005947:Glucose / Q000494:pharmacology*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D057775:Ischemic Postconditioning / Q000379:methods; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010100:Oxygen / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000517:prevention & control; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D018840:HSP70 Heat-Shock Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D005947:Glucose; D010100:Oxygen