Abstract: Hypoxia inducible factor -1(HIF-1)is a transcriptional factor induced when mammalian cells are exposed to chronic hypoxia. In this study, chronic hypoxic(H)and nomorxic(C)HeLa cells, brain tissue without hypoxia exposure(H₀), that with 1 run of hypoxia exposure(H₁)and with 4 runs of hypoxia exposure(H₄)were collected. Cellular extract were prepared and analyzed by Western blot assay to detect HIF-1α. HIF-1α could be detected in chronic hypoxic HeLa cells. No HIF-1α could be found in group H₀, while a small amount of HIF-1α and much more HIF-1α could be found in group H₁ and H₄ respectively. These results indicate that HIF-1α in brain cells increases during hypoxia preconditioning. The increase of HIF-1 is a possible mechanism for hypoxia preconditioning.

Key words: hypoxia inducible factor-1, hypoxia preconditioning, Western blot assay