<p>Myocardial ischemia-reperfusion (MI/R) injury significantly limits the clinical benefits of coronary reperfusion therapy. Ferroptosis, an iron-dependent form of regulated cell death driven by lipid peroxidation, has been implicated in myocardial ischemia-reperfusion (I/R) injury. Liproxstatin-1 (Lip-1) is a potent ferroptosis inhibitor, but its dynamic, dose-dependent effects on key molecular pathways and pathological hallmarks in the heart remain incompletely characterized. To systematically investigate the dose- and time-dependent cardioprotective effects of Lip-1 against myocardial I/R injury, with a focus on the NRF2/GPX4 pathway, iron deposition, and lysosomal integrity. Ninety Wistar rats were randomly allocated to 15 experimental groups (<i>n</i> = 6 per group): Normal (no surgery), Sham (thoracotomy without ischemia), I/R model, and I/R + Lip-1 treatment groups. Lip-1 was administered intravenously at doses of 1, 3, or 5&#xa0;mg/kg at 0, 24, 48, and 72&#xa0;h post-reperfusion initiation, with myocardial tissue and blood samples harvested 6&#xa0;h after each injection. Cardiac function was assessed by echocardiography. Myocardial infarct size was determined by Evans Blue/TTC double staining. Serum levels of CK-MB and LDH were measured as markers of myocardial injury. Analyses included Western blot for NRF2 and GPX4 expression, Prussian blue staining for iron deposition quantification, and immunofluorescence for LAMP1 localization and intensity. Statistical analysis was performed using two-way ANOVA with Tukey’s post hoc test for Lip-1 treatment groups, and t-tests or one-way ANOVA for model validation comparisons. Compared to Sham, I/R injury significantly decreased LVEF, increased infarct size, and elevated CK-MB and LDH levels (all <i>P</i> &lt; 0.0001), confirming successful model establishment. It also downregulated GPX4 expression, induced severe iron deposition, and reduced LAMP1 levels, while triggering an adaptive upregulation of NRF2. Lip-1 treatment produced dose- and time-dependent protection across all measured endpoints. It improved cardiac function, reduced infarct size, and attenuated CK-MB and LDH release, with significant dose×time interactions for infarct size (F(6,60) = 8.338, <i>P</i> &lt; 0.0001), CK-MB (F(6,60) = 6.467, <i>P</i> &lt; 0.0001), and LDH (F(6,60) = 9.021, <i>P</i> &lt; 0.0001). It dynamically modulated the NRF2/GPX4 axis, with peak GPX4 expression observed following the 48-hour administration (sampled at 54&#xa0;h post-reperfusion). Lip-1 progressively reduced iron deposition, with maximal effect observed after the 72-hour administration (sampled at 78&#xa0;h post-reperfusion), and rescued LAMP1 downregulation in later sampling points. Statistical analysis revealed significant dose×time interactions for NRF2 (F(6,60) = 200.8, <i>p</i> &lt; 0.0001), GPX4 (F(6,60) = 34.84, <i>p</i> &lt; 0.0001), and iron deposition. High-dose Lip-1 (5&#xa0;mg/kg) demonstrated superior and sustained efficacy across all parameters. Lip-1 confers multi-faceted cardioprotection against I/R injury through sequential mechanisms involving early potentiation of the NRF2/GPX4 antioxidant defense, progressive attenuation of pathological iron accumulation, and restoration of lysosomal membrane integrity. The strict dose and temporal dependency of these effects provide critical insights for optimizing ferroptosis-targeted therapeutic strategies in ischemic heart disease.</p>

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Dose- and time-dependent cardioprotection of liproxstatin-1 via sequential modulation of ferroptosis pathways after myocardial ischemia-reperfusion

  • Ziwei Huang,
  • Xixi Chen,
  • Junyi Ren,
  • Linlin Wan,
  • Miao Li,
  • Xiaowu Ma,
  • Jing Dong,
  • Hong Ran

摘要

Myocardial ischemia-reperfusion (MI/R) injury significantly limits the clinical benefits of coronary reperfusion therapy. Ferroptosis, an iron-dependent form of regulated cell death driven by lipid peroxidation, has been implicated in myocardial ischemia-reperfusion (I/R) injury. Liproxstatin-1 (Lip-1) is a potent ferroptosis inhibitor, but its dynamic, dose-dependent effects on key molecular pathways and pathological hallmarks in the heart remain incompletely characterized. To systematically investigate the dose- and time-dependent cardioprotective effects of Lip-1 against myocardial I/R injury, with a focus on the NRF2/GPX4 pathway, iron deposition, and lysosomal integrity. Ninety Wistar rats were randomly allocated to 15 experimental groups (n = 6 per group): Normal (no surgery), Sham (thoracotomy without ischemia), I/R model, and I/R + Lip-1 treatment groups. Lip-1 was administered intravenously at doses of 1, 3, or 5 mg/kg at 0, 24, 48, and 72 h post-reperfusion initiation, with myocardial tissue and blood samples harvested 6 h after each injection. Cardiac function was assessed by echocardiography. Myocardial infarct size was determined by Evans Blue/TTC double staining. Serum levels of CK-MB and LDH were measured as markers of myocardial injury. Analyses included Western blot for NRF2 and GPX4 expression, Prussian blue staining for iron deposition quantification, and immunofluorescence for LAMP1 localization and intensity. Statistical analysis was performed using two-way ANOVA with Tukey’s post hoc test for Lip-1 treatment groups, and t-tests or one-way ANOVA for model validation comparisons. Compared to Sham, I/R injury significantly decreased LVEF, increased infarct size, and elevated CK-MB and LDH levels (all P < 0.0001), confirming successful model establishment. It also downregulated GPX4 expression, induced severe iron deposition, and reduced LAMP1 levels, while triggering an adaptive upregulation of NRF2. Lip-1 treatment produced dose- and time-dependent protection across all measured endpoints. It improved cardiac function, reduced infarct size, and attenuated CK-MB and LDH release, with significant dose×time interactions for infarct size (F(6,60) = 8.338, P < 0.0001), CK-MB (F(6,60) = 6.467, P < 0.0001), and LDH (F(6,60) = 9.021, P < 0.0001). It dynamically modulated the NRF2/GPX4 axis, with peak GPX4 expression observed following the 48-hour administration (sampled at 54 h post-reperfusion). Lip-1 progressively reduced iron deposition, with maximal effect observed after the 72-hour administration (sampled at 78 h post-reperfusion), and rescued LAMP1 downregulation in later sampling points. Statistical analysis revealed significant dose×time interactions for NRF2 (F(6,60) = 200.8, p < 0.0001), GPX4 (F(6,60) = 34.84, p < 0.0001), and iron deposition. High-dose Lip-1 (5 mg/kg) demonstrated superior and sustained efficacy across all parameters. Lip-1 confers multi-faceted cardioprotection against I/R injury through sequential mechanisms involving early potentiation of the NRF2/GPX4 antioxidant defense, progressive attenuation of pathological iron accumulation, and restoration of lysosomal membrane integrity. The strict dose and temporal dependency of these effects provide critical insights for optimizing ferroptosis-targeted therapeutic strategies in ischemic heart disease.