[Therapeutic Effect of Cang-Ai Volatile Oil on High-Altitude Rats With Cardiac Hypertrophy Through Modulation of Oxidative Stress Response].

OBJECTIVE: To explore the therapeutic effect of Cang-ai volatile oil (CAVO) on rats with myocardial hypertrophy (MH) exposed to the hypobaric hypoxic environment of the Qinghai-Tibet Plateau using 7.0-tesla (7.0T) cardiac magnetic resonance imaging (CMR). METHODS: A total of 50 male specific pathogen-free (SPF) Sprague-Dawley (SD) rats were randomly assigned to a low-altitude control (CON) group, hypobaric hypoxia (HH) group, myocardial hypertrophy modeling (MH) group, MH modeling plus CAVO treatment (MH+CAVO) group, and MH modeling plus benadryl hydrochloride treatment (MH+RX) group, with 10 rats in each group. Except for the CON group, the rats in all the groups were kept and fed in the standard way for 8 weeks in a high-altitude environment (at 4250 m above sea level), and then given the corresponding treatment drugs by gastric gavage. Afterwards, 7.0T high field strength CMR was used to measure left ventricular (LV) function and myocardial strain. Hematoxylin-eosin (HE) staining and Masson staining were performed to observe myocardial interstitial fibrosis. Wheat germ agglutinin (WGA) staining was performed to analyze the cross-sectional area of cardiomyocytes. Transmission electron microscopy was used to observe the ultrastructural changes of the myocardium. Serum levels of cardiac troponin T (cTnT), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione peroxidase (GSH-PX) were measured by ELISA. RESULTS: Compared with those of the control group, the MH group had significantly lower left ventricular global circumferential strain (LVGCS) at (－18.85±1.67)% and left ventricular global longitudinal strain (LVGLS) at (－20.39±1.48)% (P<0.05). However, the MH+CAVO group had significantly higher LVGCS at (－22.10±1.08)% and LVGLS at (－24.60±1.72)% compared with those of the MH group (both P<0.05), indicating that CAVO treatment improved LV function. The MH group had a decreased level of serum glutathione peroxidase (GSH-Px) in comparison with the CON group ([1173.49±27.10] U/mL vs. [300.83±47.25] U/mL, P<0.01), a decreased SOD level in comparison with the CON group ([302.27±3.65] U/mL vs. [105.96±4.03] U/mL, P<0.01), and an increased level of serum malondialdehyde (MDA) in comparison with the CON group ([57.91±1.13] μmol/L vs. [6.65±2.99] μmol/L, P<0.01), suggesting that the antioxidant capacity of rats in the MH group was decreased. After CAVO intervention, rats in the MH+CAVO group exhibited an increase in the serum levels of SOD at (278.51±5.97) U/mL and GSH-Px at (961.82±17.56) U/mL, as well as a decrease in MDA at (17.79±1.33) μmol/L (all P<0.05). CONCLUSION: CAVO can effectively improve cardiac function in rats with cardiac hypertrophy exposed to high-altitude environment by modulating oxidative stress and ameliorating cardiac hypertrophy.