Objective:To observe the dynamic change of heme oxygenase-1（HO-1）and heme oxygenase-2（HO-2）in the livers of the rats with cerebral hypoperfusion

and to explore their significance.Methods:Sixty 4-month-aged male SD rats

weighing 250 to300 g

were enrolled and divided into model groups and sham group.Model groups were performed by permanent bilateral common carotid arteries occlusion（2 vessel occlusion

2 VO）and randomly divided into 5 groups（1

7

14

21

28 d after 2 VO）.The expressions of HO-1 and HO-2 at mRNA and protein levels were detected by RT-PCR and Western blot.HO activities were evaluated by ultraviolet specrophotometer.Results:RT-PCR and Western blot results showed that the expression of HO-1 mRNA and protein were increased in the livers on 1 d after 2 VO

and reached a peak on 7 d after 2 VO（P=0.000

P=0.000）

accompanied by enhancement of HO activity（P=0.000）.Nevertheless

RT-PCR and Western blot showed that the expression of HO-2 didn’t change with time gradient（P=0.604

P=0.329）.Conclusion:The activity of heme oxygenase and HO-1 mRNA and protein are increased in the livers of the rats with chronic cerebral hypoperfusion

but the expression of HO-2 at mRNA and protein level is not statistically changed

suggesting that HO-1 may play a protective role against liver injury induced by chronic cerebral hypoperfusion.