[Protective effect of intermittent hypobaric hypoxia on cardiomyocytes injury induced by hydrogen peroxide]

Abstract

Objective: To observe the protective effect and mechanism of intermittent hypobaric hypoxia (IHH) on cardiomyocytes induced by hydrogen dioxide.

Methods: Male guinea pigs were divided randomly into two groups (n = 10): intermittent hypoxia group (IHH), and control group (non-IHH). The IHH guinea pigs were exposed to a simulated 5,000 m high altitude and hypoxia in hypobaric chamber for 28 d, 6 h/d. The control guinea pigs were kept in the same environment as IHH except hypoxia exposure. Cardiomyocytes were enzymatically isolated from left ventricle of non-CIHH or CIHH guinea pigs. The contractile was assessed in guinea pigs by a video-based motion edge-detection system. The contents and activities of malondialdehyde(MDA), lactate hydrogenase(LDH) and antioxidant enzymes were evaluated by using biochemical methods.

Results: 1. Hydrogen peroxide could induce contractile and diastole dysfunction, the latent period was longer in IHH cardiac myocytes. 2. After hydrogen peroxide(300 micromol/L, 10 min) perfusion, LDH and MDA contents in supernatant increased significantly in non-IHH and CIHH cardiomyocytes (P < 0.01), Whereas the contents of MDA and LDH in IHH cardiomyocytes were lower than those in non-IHH cardiomyocytes (P < 0.01). 3. The activities of superoxide dismutase (SOD) and catalase (CAT) were significantly increased in the myocardium of IHH guinea pigs, after hydrogen peroxide (300 micromol/L, 10 min) perfusion, SOD and CAT activities decreased significantly in non-IHH and CIHH cardiomyocytes (P < 0.01), whereas the activities of SOD and CAT in CIHH cardiomyocytes were still higher than those in non-IHH cardiomyocytes.

Conclusion: IHH had a protective effect on cardiomyocytes injury induced by hydrogen peroxide, which might relate with its antioxidation effects.