Reperfusion injury after myocardial ischemia is primarily mediated by which of the following mechanisms?
- A Continued ATP depletion preventing membrane pump recovery
- B Lactic acidosis leading to lysosomal enzyme release
- C Burst of reactive oxygen species generation from mitochondria and xanthine oxidase upon reoxygenation ✓
- D Complement-independent neutrophil margination
Correct answer: C. Burst of reactive oxygen species generation from mitochondria and xanthine oxidase upon reoxygenation
Explanation
Reperfusion injury paradoxically worsens damage upon restoration of blood flow. The sudden reintroduction of oxygen to ischemic cells generates a burst of reactive oxygen species (ROS) from dysfunctional mitochondria and activated xanthine oxidase. ROS cause membrane lipid peroxidation, protein oxidation, and DNA damage, compounding ischemic injury. Mitochondrial permeability transition pore (mPTP) opening is also a key mechanism during reperfusion.
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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