Effects of hesunate on cell autophagy and apoptosis in rats with myocardial ischemia reperfusion injury by regulating TLR4-mTOR-ULK1 signaling pathway
Zhang Weifeng
Ma Hailong
Zhang Jinling
Abstract：Objective To investigate the effect and mechanism of hesunate(HES)on cell autophagy and apoptosis in rats with myocardial ischemia reperfusion injury(MIRI).Methods SD rats were randomly grouped into sham operation group(Sham group),MIRI group,low-dose HES(HES-L,15 mg/kg)group,high-dose HES(HES-H,30 mg/kg)group and HES-H+Toll like receptor 4(TLR4)inhibitor(HES 30 mg/kg+Compound C 0.2 mg/kg)group,and were administered continuously for 7 days.The MIRI model was established in rats other than Sham group using coronary ligation method,after 24 hours,left ventricular hemodynamic parameters[including left ventricular end diastolic pressure(LVEDP),maximal left ventricular pressure rising rate(dp/dtmax)and maximal left ventricular pressure decreasing rate(-dp/dtmax)]were measured,TdT-mediated dUTP nick end labeling(TUNEL)method was applied to detecting cardiomyocyte apoptosis,myocardial infarction area was measured by triphenyltetrazolium chloride(TTC)staining,the levels of malondialdehyde(MDA)and superoxide dismutase(SOD)in myocardial tissue were detected by enzyme linked immunosorbent assay(ELISA),and Western blotting was applied to detecting the expression of microtubule associated protein 1-light chain 3(LC3)Ⅱ,LC3Ⅰ,autophagy effector protein(Beclin1),TLR4,phosphorylated(p)-TLR4(p-TLR4),mammalian target of rapamycin(mTOR),p-mTOR,unc-51-like autophagy activated kinase 1(ULK1)and p-ULK1 in rat cardiac tissue.Results Compared with Sham group,MIRI group showed mitochondrial damage and autophagic vacuole formation.The levels of LVEDP[mmHg(1 mmHg≈0.133 kPa):14.22±2.12 vs.5.44±0.83],myocardial cell apoptosis rate[(31.52±4.01)%vs.(2.41±0.26)%],myocardial infarction area(mm2:43.68±3.86 vs.0.00),myocardial tissue MDA(ng/L:8.25±1.03 vs.3.71±0.65),p-mTOR/mTOR(0.76±0.08 vs.0.33±0.04)and p-ULK1/ULK1(0.69±0.08 vs.0.22±0.04)showed significant increase,while dp/dtmax(mmHg/s:3 441.43±289.25 vs.4 910.57±350.12),-dp/dtmax(mmHg/s:2 588.96±260.23 vs.3 845.94±364.19),myocardial tissue LC3Ⅱ/LC3Ⅰ(1.13±0.14 vs.2.35±0.21),Beclin1(0.35±0.06 vs.0.87±0.09),and p-TLR4/TLR4(0.40±0.05 vs.0.84±0.10)showed significant decrease(all P<0.05).Compared with MIRI group,the mitochondrial damage in HES-L and HES-H groups was alleviated,and autophagic vacuoles were rare.The levels of LVEDP(mmHg:11.56±1.60,7.88±1.21 vs.14.22±2.12),myocardial cell apoptosis rate[(25.52±3.11)%,(17.54±1.89)%vs.(31.52±4.01)%],myocardial infarction area(mm2:36.67±3.58,29.58±3.04 vs.43.68±3.86),myocardial tissue MDA(ng/L:6.98±0.65,4.12±0.48 vs.8.25±1.03),p-mTOR/mTOR(0.60±0.07,0.45±0.05 vs.0.76±0.08),p-ULK1/ULK1(0.54±0.05,0.32±0.04 vs.0.69±0.08)were significantly reduced,and dp/dtmax(mmHg/s:3 972.82±310.17,4 442.97±396.24 vs.3 441.43±289.25),-dp/dtmax(mmHg/s:3 152.30±312.18,3 430.57±324.24 vs.2 588.96±260.23),LC3Ⅱ/LC3Ⅰ in myocardial tissue(1.76±0.18,2.01±0.20 vs.1.13±0.14),Beclin1(0.56±0.07,0.79±0.08 vs.0.35±0.06)and p-TLR4/TLR4(0.55±0.06,0.73±0.08 vs.0.40±0.05)were significantly elevated(all P<0.05).Conclusion HES may promote autophagy and inhibit apoptosis of myocardial cells in MIRI rats by activating TLR4-mTOR-ULK1 signaling pathway.
Keywords：Myocardial ischemia reperfusion injuryHesperetinToll like receptor 4Mammalian target of rapamycinunc-51 like autophagy activated kinase 1AutophagyApoptosis
Publication Date：2024-06-15
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 133-138 )