Abstract: Objective To observe the effects of hypoxia simulated by cobalt chloride on the expression of hypoxia-inducible factor-1α(HIF-1α) and vascular endothelial growth factor(VEGF) in murine macrophage Raw264.7 induced beforehand by using LPS . Methods Raw264.7 were divided into control group，LPS（1mg/L）group，CoCl2（100μmol/L）group and LPS pre-treatment(LPS-Pre) group and incubated respectively in the culture containing corresponding reagent. The macrophages of LPS pre-treatment group were at first incubated for 8 hours in the culture with LPS of 1mg/L and then were transferred into the culture containing CoCl2 of 100μmol/L. HIF-1α and VEGF’ mRNA were detected by RT-PCR；protein of HIF-1α and VEGF were analyzed by Western blot and immunocytochemistry. Results Compared with those of control, mRNA and protein expression of both HIF-1α and VEGF can be up-regulated in CoCl2 group and LPS-Pre group（p<0.05）.Moreover, cells were pre-treated with LPS and followed activated by CoCl2, HIF-1α’s protein significantly higher（p<0.05）than that of induced only by CoCl2. Conclusion Pre-treatment with LPS can up-regulate HIF-1α and VEGF’s protein at the post-transcriptional level in macrophages under hypoxia environment.

Key words: Key words: hypoxia, inflammation, LPS, CoCl2, HIF-1α