title: [The up-regulation of hypoxia inducible factor-1α by hypoxic postconditioning reduces hypoxia/reoxygenation-induced injury in heart-derived H9c2 cells].
abstract: The aim of the present study was to explore the effects of hypoxic postconditioning (PostC) on heart-derived H9c2 cells injury induced by hypoxia/reoxygenation (H/R) and the expression of hypoxia inducible factor-1α (HIF-1α), and to analyze the relationship between them. Cultured H9c2 cardiac muscle cells were subjected to 3-hour hypoxia and 2-hour reoxygenation to simulate ischemia and reperfusion, or underwent 3 cycles of 5-min reoxygenation and 5-min hypoxia preceding the long reoxygenation to simulate ischemic postconditioning. Cell viability, lactate dehydrogenase (LDH) activity, and caspase-3 activity were detected respectively to investigate the cell injury induced by H/R. The level of HIF-1α mRNA was measured by real-time PCR. Western blot was used to determine HIF-1α protein level. The results showed that postconditioning significantly increased H9c2 cell viability, reduced the activity of LDH and caspase-3. Simultaneously, postconditioning up-regulated the HIF-1α protein level. Moreover, after DMOG, an inhibitor of proline hydroxylase (PHD) which targeted to HIF-1α degradation, was used to stabilize HIF-1α protein level, the reduction of H9c2 cells injury was comparable to that by postconditioning. There was a significant linear positive relationship between HIF-1α protein level and cell viability (r = 0.743, P < 0.01). After HIF-1α gene was silenced by siRNA, the cardio-protective effects of postconditioning was significantly weakened. These data suggest that up-regulation of HIF-1α plays an important role in the cardio-protection of postconditioning.
authors.affiliation: Department of Physiology, Shanxi University of Traditional Chinese Medicine, Taiyuan 030024, China; Department of Physiology, Shanxi Medical University, Taiyuan 030001, China; School of Basic Medical Sciences, and Cardiovascular Research Institute, Capital Medical University, Beijing 100069, China. E-mail: zhaohx5@126.com.
authors.forename: Huan-Xin
authors.initials: HX
authors.lastname: Zhao
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Yao
authors.forename: Ye
authors.initials: Y
authors.lastname: Wu
authors.forename: Rong
authors.initials: R
authors.lastname: Yang
authors.forename: Rong-Rui
authors.initials: RR
authors.lastname: Zhao
authors.forename: Hui-Rong
authors.initials: HR
authors.lastname: Liu
mesh_terms: D000818:Animals; D053148:Caspase 3 / Q000378:metabolism; D015687:Cell Hypoxia; D002460:Cell Line; D002470:Cell Survival; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D057775:Ischemic Postconditioning; D032383:Myocytes, Cardiac / Q000378:metabolism*; D051381:Rats; D015854:Up-Regulation
chemical_list: C497444:Hif1a protein, rat; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C505410:Casp3 protein, rat; D053148:Caspase 3