Induction of the Expression of Heme Oxygenase Gene in PC12 Cells by Hypoxia

摘要

To investigate the expression of the HO-1 gene in PC12 cells in hypoxic environment and gain further insight to the role of HO-1 in cerebral ischemia, PC12 cells were exposed to hy-poxia environment (95 % N_2, 5 % CO_2) for 0. 5 h, 1 h, 4 h, 8 h, 12 h, 24 h respectively. The level of HO-1 mRNA was examined by reverse transcriptase polymerase chain reaction (RT-PCR); the volume of COHb in the media were measured spectrophotometrically and the cGMP concentration of PC12 cell extracts was determined by radioimmunoassay. We found that after exposure to hypoxia for 1 h, 4 h, 8 h, 12 h, 24 h, HO-1 mRNA increased by 3%, 4%, 17%, 31% , 36% as compared with that in control group respectively (P<0. 01 or P<0. 05); the COHb increased by 12% , 29%, 59% , 88%, 94% as compared with that in control group respectively (P<0. 01 or P<0. 05) , and the cGMP concentration were 2. 2, 3. 4, 5. 2, 8. 1, 10. 9-fold as that of the control group (P<0. 01). We are led to conclude that hypoxia induced the expression of HO-1 gene, the production of endogenous CO, and the concentration of cGMP was elevated as well.