ABSTRACT
OBJECTIVE: To investigate the effect of trifluoro-icaritin (ICTF) on myocardial ischemia/reperfusion injury (MI/RI) in rats and to explore whether it plays a role in regulating autophagy through the serine/threonine kinase/mammalian target of rapamycin (Akt/mTOR) signaling pathway. METHODS: Male SD rats were ligated for 45 min and reperfused for 60 min to establish an MI/RI model. The rats were divided into sham, MI/RI model and model+ICTF 0.5, 1.0 and 2.0 mg·kg-1groups. II lead electrocardiogram (ECG) in T wave and ST segment changes were recorded. The area of myocardial infarction was determined by TTC. The protein levels and phosphorylation levels of microtubule-associated protein 2/1 light chain 3 (LC3 II/LC3 I), Beclin-1, Akt and mTOR in myocardial tissues were detected by Western blotting. The level of LC3 in myocardial tissues was detected by immunofluorescence test. RESULTS: The ECG showed that the T wave (P<0.05) and ST segment (P<0.01) of the model group were significantly higher than those of the sham group after 60 min of reperfusion, while the T wave (P<0.05) and ST segment (P<0.01) of the ICTF 1.0 mg·kg-1group were obviously lower than those of the model group. TTC staining of heart sections showed that the area of myocardial infarction in the model group was larger than in the sham group (P<0.01), while that in the ICTF 1.0 mg·kg1group was smaller than in the model group (P<0.01). Western blotting results showed that compared with the sham group, the ratios of LC3 II/LC3 I (P<0.01) and p-Beclin-1/Beclin-1 (P<0.05) in the model group were significantly increased, while Akt (P<0.01) and mTOR (P<0.05) were decreased. In addition, compared with the model group, the ratio of LC3 II/LC3 I (P<0.01) and p-Beclin-1/Beclin-1 (P<0.01) in the ICTF 1.0 mg·kg-1group was reduced, and the phosphorylation levels of Akt (P<0.01) and mTOR (P<0.01) were increased. Immunofluorescence results of frozen sections of myocardial tissues showed that LC3 protein expression increased in the model group compared with the sham group (P<0.01), but decreased in the ICTF 1.0 mg·kg-1group compared with the model group (P<0.01). CONCLUSION: ICTF has a protective effect on myocardial ischemia/reperfusion injury in rats, and its mechanism may be related to the regulation of Akt/mTOR signaling pathway to inhibit excessive autophagy.