Apoptosis and pyroptosis inhibitors exerted greater cardioprotection against cardiac I/R injury than ferroptosis inhibitor in prediabetic rats via an improvement of mitochondrial membrane potential
N Apaijai, H Pintana, A Khongkaew, S C Chattipakorn, N ChattipakornAbstract
Background
Programmed cell death is a major contributor to myocardial infarct expansion following cardiac ischemia/reperfusion (I/R) injury. Acute inhibition of apoptosis and ferroptosis prior to ischemia has been shown to reduce cardiac I/R injury. However, the effects of chronic inhibition of apoptosis, ferroptosis, and pyroptosis during cardiac I/R injury have not yet been investigated.
Purpose
To investigate whether pharmacological inhibition of apoptosis, ferroptosis, and pyroptosis can alleviate infarct size, cardiac dysfunction, and mitochondrial dysfunction in prediabetic rats subjected to I/R injury.
Methods
Male rats were fed either a high-fat diet (HFD) to induce prediabetes or a normal diet (ND) as a control for 24 weeks. Subsequently, HFD-fed rats were divided into four subgroups: (1) vehicle (normal saline solution, subcutaneous injection), (2) apoptosis inhibitor (Z-VAD, 1 mg/kg, subcutaneous injection), (3) ferroptosis inhibitor (Fer-1, 1 mg/kg, subcutaneous injection), and (4) pyroptosis inhibitor (disulfiram, 50 mg/kg, oral gavage). Rats received their assigned intervention for an additional 2 weeks before being subjected to 30 minutes of LAD ligation to induce ischemia followed by 2 hours of reperfusion. Left ventricular function, arrhythmia score, infarct size, and mitochondrial function were assessed.
Results
HFD-fed rats exhibited more severe cardiac I/R injury than ND-fed rats, as indicated by a larger infarct size, greater left ventricular (LV) dysfunction, and more pronounced mitochondrial dysfunction. Treatment with programmed cell death inhibitors significantly reduced infarct size to a similar extent across groups (Fig 1A). However, treatment with apoptosis and pyroptosis inhibitors provided greater improvement in LV function, as evidenced by a greater reduction in LV end-diastolic pressure and a higher LV ejection fraction, compared with ferroptosis inhibition (Fig 1B). Mitochondrial function analysis showed that although all programmed cell death inhibitors similarly attenuated mitochondrial oxidative stress, apoptosis and pyroptosis inhibitors greater attenuated mitochondrial depolarization (Fig 1C) and mitochondrial swelling. Arrhythmia scores were comparable among groups regardless of diet or programmed cell death intervention (Fig 1D).
Conclusion
Although programmed cell death inhibitors effectively reduced infarct size in prediabetic rats with cardiac I/R injury, apoptosis and pyroptosis inhibition provided superior cardioprotection compared with ferroptosis inhibition, as demonstrated by greater improvements in mitochondrial and LV function.