| Objective: Studying the change of heme oxygenaese-1 (HO-1) under intermittent hypoxia condition and evaluating the relationship between HO-1 and blood pressure of hypoxic rats. Methods: 24 Sprague-Dawley (SD) male rats were randomly divided into intermittent hypoxia group (A), control group (B)and unhandled group (C). Group A was recreated by exposure to intermittent normobaric hypoxic environment (expose chamber O2[fractional concentration of chamber O2] nadir 5%—6% with return to 21% in 60 seconds of 8 h/day). Group B inhaled air in the same size air box, group C just inhaled air in the room. Left carotid artery catheterization was employed to measure the carotid artery pressure (CAP) of rats. Plasma carbon monoxide (CO ) was detected according the method introduced by Chalmers. Transcriptase polymerase chain reaction (RT-PCR) was performed to detect the levels of HO-1 mRNA expression in the rat organs .The expression of HO-1 protein was determined by immunohistochemistry and Western Blot. Results: Blood pressure: steady hypertension of hypoxemic rats was found after 35 days intermittent hypoxia. The mean blood pressure in group A was significantly higher than group B and group C. The concentration of plasma CO in group A was not elevated compared with those in group B and C (P>0.05), The expression of HO-1 of lung, liver and spleen in group A detected by immunohistochemistry and Western Blot was higher than group B and C. HO-1mRNA expression of lung, liver and spleen in group A was also higher than group B and C(P<0.01). But the HO-1 mRNA and HO-1 protein expression of kidney, especially medulla, in hypoxic rats had significant decrease than group B and C(P<0.05). There were significant positive relationship between mCAP and HO-1 mRAN expression of liver , spleen, and lung in hypoxic rats, but there were significant negative relationship between mCAP and HO-1 mRAN and protein expression of kidney in hypoxic rats(r=-0.42N -0.38). Conclusions: The higher blood pressure of hypoxic rats was set up after 35 days intermittent hypoxia.HO-1 gene and protein expression in lung, liver and spleen of hypoxic rats were higher than group B and C, and suggested it might play a protective role in OSAHS. Plasma CO in hypoxic rats did not have significant increase than group B and C, it might be one of the causes of hypertension for hypoxic rats. HO-1 expression in kidney especially medulla of hypoxic rats had a downregulation, it might be an important cause of systemic hypertension. |
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