Time course of heme oxygenase-1 and oxidative stress after experimental intracerebral hemorrhage

Heme oxygenase-1 (HO-1), the rate-limiting enzyme for heme catabolism and iron production, its role in intracerebral hemorrhage (ICH) is controversial. The study was to investigate correlations between brain oxidative injury and HO-1 after experimental ICH.

Sprague-Dawley rats received intra-striatal infusions of 100 μl autologous whole blood as ICH models. HO-1 were examined by immunohistochemical and reverse transcription polymerase chain reaction (RT-PCR) analysis. Brain oxidative stress was quantitated by malondialdehyde (MDA); antioxidation were measured by copper-zinc superoxide dismutase (Cu/Zn-SOD) activity using RT-PCR assay.

The expression of the HO-1 upregulated and reached its peak at days 3 and 7 after ICH (P < 0.01). There was a significant increase of MDA and a top at 3-day post-ICH (P < 0.01); Cu/Zn-SOD was upregulated post-ICH and reached the top at day 7 (P < 0.001); HO-1 was correlated significantly with brain MDA content at days 7 and 14 following ICH (r = 0.435-0.501, P < 0.001) but there is no definite correlation between them on 1 to 3 days (P > 0.05); conversely, HO-1 was correlated significantly with Cu/Zn-SOD on 1 to 3 days after ICH (r = 0.433-0.621, P < 0.001) but there is no definite correlation between them at days 7 and 14 (P > 0.05).

HO-1 has both antioxidant and prooxidant properties in ICH. The early upregulation of HO-1 possibly fit with the events and be protective against oxidative stress, whereas its overexpression in the late stages may result in its dysfunction and be toxic. So it should be prudent to intervene ICH with the inhibitor/activator of HO-1.